Ion binder for solid electrodes

Abstract

An electrode for an all-solid-state energy storage device comprising an electrode composition comprising an electroactive material and an internal ion binder in the form of a complex of at least one organic ionic plastic crystal (OIPC) and an ion transport salt, the electrode composition supporting performance of the electrode equivalent to that using a liquid electrolyte.

Description

[Technical field]

[0001] The present invention relates to a novel class of conductive functional ion-binding agents with plastic crystalline properties for use, for example, in electrodes for solid state batteries. [Background technology]

[0002] Currently, lithium-ion batteries (LIBs), which are composed of a carbon-based anode and a lithium metal oxide cathode separated by a liquid electrolyte, dominate the battery market, offering long life and high energy density. With the rapid expansion of the electric vehicle (EV) market, there is an ever-increasing demand for large-scale use of LIBs. However, in order for LIBs to be widely used in such large-scale applications, their safety must be ensured. However, at the cell chemistry level, LIBs use flammable organic liquid electrolytes. Conventional liquid electrolytes are an obstacle from a safety perspective due to their high flammability, which is more serious in next-generation batteries where lithium metal anodes are used, as they are prone to short circuits. As a result, all-solid-state batteries (ASSBs) have attracted much attention due to the fact that they are leak-free and limit the growth of lithium dendrites by the presence of a physical barrier. ASSBs, which contain a solid electrolyte as an ion-conducting path, have higher thermal stability in LIBs than conventional liquid electrolytes. One goal of the present invention is to provide a cost-effective ASSB with performance comparable to LIBs, which means that the replacement of LIBs by ASSBs becomes a viable possibility.

[0003] In liquid-based batteries, the pores of the electrode are filled with liquid electrolyte and the addition of interconnected carbon provides sufficient ionic and electronic pathways within the electrode, whereas in true solid-state systems, the electrode remains liquid-dry and therefore devoid of mobile ions for doping and dedoping of the active material. As a result, a shift from promising performance porous electrodes to dense electrodes has been proposed, where ion-conducting binders such as ionic liquids are used to provide the necessary ionic conductivity, while the use of traditional carbon additives continues to provide electronic conduction in solid-state devices. However, ionic conductivity in conducting polymers has rarely been reported, and the use of ionic liquids does not overcome problems associated with liquid electrolytes, such as leakage.

[0004] Another important factor is the processability of the solid electrodes, including active materials and solid electrolyte (plus conductive additives and binders, if necessary), to current LIB production lines. A highly compatible electrode preparation method will facilitate the adoption of ASSBs in energy storage applications. Inorganic solid electrolytes are promising materials in terms of their bulk ionic conductivity, but require additional high temperature / pressure steps to form void-free contacts between the solid electrolyte and the active materials of the electrodes. In this context, organic solid electrolytes become attractive candidates due to their excellent processability, which allows them to simply utilize current LIB fabrication techniques without implementing additional low-throughput processes.

[0005] Organic ionic plastic crystals (OIPCs) used in organic solid electrolytes are an emerging class of ionic conductors. OIPCs are solid analogues of ionic liquids and inherit the advantages of ionic properties including low flammability, negligible vapor pressure, and high thermal and chemical stability. OIPCs have been used in the interlayer between the cathode and anode, but have never been used as an intrinsic component of the electrode slurry, in a solid electrode composition for electrode casting / consolidation, or inside the electrode composition slurry. Summary of the Invention [Means for solving the problem]

[0006] Described herein are electrodes and all-solid-state energy storage devices comprising the electrodes, the electrodes comprising an electrode composition comprising an electroactive material and an internal ionic binder in the form of at least one organic ionic plastic crystal (OIPC). Desirably, the electrodes do not comprise an ion-conducting polymer electrolyte. Suitably, the internal ionic binder is a preformed complex of an organic ionic plastic crystal (OIPC) and a transporting ionic salt. It should be understood that the preformed complex binder is inherently associated with the other electrode components during blending and slurry formation, and is itself subject to the same processing, e.g., solvent evaporation, compaction or densification, etc., as the active components in the electrode. It should be understood that the preformed complex binder is not added during the manufacture of the preformed electrode, e.g., by drop casting in solution. It has been found that electrodes without dry polymer electrolyte are sufficiently ionically conductive and stable to cycling in ASS devices to provide comparable cycling and / or capacity storage and release performance to comparable devices with liquid electrolytes. The present invention provides an energy storage device comprising one or more of the electrodes of the present invention, a counter electrode, and an electrolyte, preferably a solid electrolyte.

[0007] The present invention provides for the use of organic ionic plastic crystals (OPICs) as internal ion binders in conversion material electrodes, in intercalation electrodes, and in alloyed electrodes.

[0008] In one aspect, the invention provides an electrochemical energy storage device comprising a pair of at least one positive electrode and at least one negative electrode, where at least one electrode is a solid electrode in the form of a dry electrode composition, comprising particles of an electrochemically active material; particles of an optional electronically conductive additive; particles of an optional non-ionically conductive polymeric binder; and an internal ionic binder in the form of a preformed intimate complex of an organic ionic plastic crystal (OIPC) and a transport ion salt. The invention extends to a cell (e.g., a half cell) in which the positive electrode is the working electrode and the negative electrode is the counter electrode.

[0009] Preferably, the voids between the particles are filled with an internal ion-binding agent. The voids block or interrupt ion conduction pathways in the electrode. By filling the voids with the OIPC complex, such interrupted ion conduction pathways are completed. Thus, in the electrodes of the present invention, the OIPC complex completes or creates new ion conduction pathways that would not otherwise exist.

[0010] Desirably, the device is configured as an all-solid-state energy storage device and further includes an ion transport interlayer disposed between each pair of electrodes, where a separated portion of the interlayer is in direct contact with each electrode of a pair, and where the contact between the ion transport interlayer and each electrode includes substantially void-free contact.

[0011] In another aspect, the present invention provides an all-solid-state energy device comprising a pair of at least one positive electrode and at least one negative electrode, wherein the negative electrode is an alloyed or intercalated solid negative electrode comprising a dry electrode composition comprising particles of an electrochemically active material selected from hard carbon, graphite; silicon; phosphorus; selenium; antimony; bismuth; lithium alloys such as lithium titanate, particularly lithium titanate; or metallic anode materials such as lithium metal and sodium metal; particles of an optional electronically conductive additive; particles of an optional non-ionically conductive polymeric binder; and an internal ionic binder in the form of a preformed intimate complex of an organic ionic plastic crystal (OIPC) selected from the group consisting of CMpyrBF; CMpyrFSI; and CMpyrTFSI, and a transport ion salt selected from the group consisting of LiFSI, LiBF, LiTFSI, LiOTf, NaFSI, NaBF, NaTSI, NaTFSI, or NaOTf.

[0012] In a fifth aspect, the present invention provides an all-solid-state energy device comprising at least one pair of positive and at least one negative electrode, and an ion transporting interlayer disposed between each pair of electrodes, the interlayer comprising at least one organic ion plastic crystal (OIPC) selected from the group consisting of CMpyrBF4; CMpyrFSI; and CMpyrTFSI, and a transporting ion salt selected from the group consisting of LiFSI, LiBF4, LiTFSI, LiOTf2, NaFSI, NaBF4, NaTSI, NaTFSI, or NaOTf2, wherein a separate portion of the interlayer is in direct contact with each of the pair of electrodes, and the negative electrode is an ion-conducting polymer electrolyte or a model electrolyte of the ion-conducting polymer electrolyte. In one embodiment, the present invention provides an all-solid-state energy device comprising a dry electrode composition which is a nomer-free alloy-type or intercalation-type solid anode and which comprises particles of an electrochemically active material selected from hard carbon, graphite; silicon; phosphorus; selenium; antimony; bismuth; lithium alloys such as lithium titanate, particularly lithium titanate; or metallic anode materials such as lithium metal and sodium metal; particles of an optional electronically conductive additive; particles of an optional non-ionically conductive polymeric binder; and an internal ionic binder in the form of a preformed intimate complex of an organic ionic plastic crystal (OIPC) and a transport ion salt, the OIPC and transport ion salt being the same as the ion transport interlayer.

[0013] Desirably, the OIPC complex is a preformed mixture of, for example, [C2mpyr][FSI] and LiFSI.ss. Desirably, the all-solid-state device has a negative electrode that is a silicon or graphite electrode.

[0014] When the terms "comprise", "comprises" and "comprising" are used in this specification (including the claims), they are to be construed as specifying stated features, integers, steps or components but not excluding the presence of one or more other features, integers, steps or components or groups thereof.

[0015] Further aspects of the invention appear below in the detailed description of the invention. Embodiments of the present invention are herein illustrated, by way of example only, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0016] [Figure 1a] FIG. 1 shows a schematic of a procedure for forming a solid-state device comprising the graphite-OIPC:salt ion binder of the present invention and its configuration in an all-solid-state half-cell with Li metal as the counter electrode, where the intermediate layer is a membrane in the form of a composite of electrospun PVdF fibers and embedded OIPC:salt ASSB with a Li metal counter electrode. [Figure 1b] The charge-discharge curves of a solid graphite-[C2mpyr][FSI] ionic binder composite anode (70 wt% graphite anode + 30 wt% [C2mpyr][FSI] composite) compared to the charge-discharge curves of the same graphite anode with 1.0 M LiPF6 in liquid electrolyte EC-DEC-DMC (1:1:1 volume ratio) for the first three cycles at 50 °C. The comparison shows the similarity of performance. [Diagram 2] Charge-discharge curves for the first three cycles at 50 °C for (a) a solid graphite anode (no ionic binder) containing 0 wt% [C2mpyr][FSI] composite, (b) a solid graphite-[C2mpyr][FSI] composite anode containing 15 wt% [C2mpyr][FSI] composite, and (c) a solid graphite-[C2mpyr][FSI] composite anode containing 50 wt% [C2mpyr][FSI] composite. [Figure 3a]Charging curves at 50 °C for (a) a solid graphite anode without [C2mpyr][FSI] composite, (c) a solid graphite-[C2mpyr][FSI] composite anode with 15 wt% [C2mpyr][FSI] composite, (c) a solid graphite-[C2mpyr][FSI] composite anode with 50 wt% [C2mpyr][FSI] composite, and (d) a graphite anode with 1.0 M LiPF6 in EC-DEC-DMC (1:1:1 volume ratio) liquid electrolyte. (e) Capacity ratios at each charging C rate. [Figure 3b] (a) Charging curve of solid graphite-[C2mpyr][FSI] composite anode containing 30 wt% of [C2mpyr][FSI] composite; (b) Plot of capacity ratio vs. φ electrolyte / φ anode at 2C charging at 50 °C; Schematic of blocked ion transport channels and blocked filled with ion binder. It is shown that void-free contact between the current collector and electrode, and between the electrode and the interlayer, is promoted by the ion binder. [Figure 4] Plots of capacity ratio vs. φ electrolyte / φ anode at 2C charging at 50 °C are shown. The table in the figure shows the composition, void (φ void), anode (containing graphite, carbon black and Na-CMC) (φ anode), electrolyte (φ electrolyte) and solvent (φ solvent), and the volume fraction of φ electrolyte / φ solvent. (f)-(g) show the DQ / dV curves for the 0 wt%, 30 wt% and 50 wt% systems. [Diagram 5] Solid graphite-[C2mpyr][FSI] composite anodes. Charge-discharge curves at 50 °C for the 2nd, 10th, 20th, 50th, and 100th cycles for (a) a 70 wt% graphite anode + 30 wt% [C2mpyr][FSI] composite, (b) a 50 wt% graphite anode + 50 wt% [C2mpyr][FSI] composite, and (c) a solid graphite anode 0 wt% [C2mpyr][FSI], (d) capacity retention, and (e) coulombic efficiency at each cycle. [Figure 6]Shown are SEM images of (a) 0 wt% solid graphite anode and (b–e) solid graphite-[C2mpyr][FSI] composite anode; (b, d) 70 wt% graphite anode + 30 wt% [C2mpyr][FSI] composite; (c, e) 50 wt% graphite anode + 50 wt% [C2mpyr][FSI] composite. [Figure 7] 1 shows the results of EIS testing demonstrating improved contact with the addition of OIPC complex ion binding agent. [Figure 8] Examples of typical OIPC cations and anions are shown below. [Figure 9] (a) C2mpyrBF4(P12BF4), (b) Fe(BF4)2 6H2O, (c) Fe(BF4)2 6H2O / C2mpyrBF4-LiFSI and (d) Fe(BF4)2 6H2O-C2mpyrBF4-LiFSI-graphene; (e) X-ray diffraction. [Figure 10] (a) CV curves of Fe(BF4)2·6H2O / C2mpyrBF4 / LiFSI / graphene cathode in the voltage range of 2.0 V to 4.0 V at a scan rate of 0.1 mV / s, (b) rate performance, and (c) electrochemical impedance spectroscopy (EIS) plots of Fe(BF4)2·6H2O / C2mpyrBF4 / LiFSI / graphene and Fe(BF4)2·6H2O / CMC / LiFSI / graphene tested at 50 °C; (d) first galvanostatic charge-discharge cycling of Fe(BF4)26H2O / C2mpyrBF4 / LiFSI / graphene at different current rates. The electrolyte is PVDF film supported Pdadma / C3mpyrFSI / LiFSI and the anode is Li metal. [Figure 11] (a) First galvanostatic charge-discharge cycling of Fe(BF4)26H2O / C2mpyrBF4 / LiFSI / graphene and Fe(BF4)26H2O / CMC / LiFSI / graphene at 50 °C with a cathode loading of 0.8 mg / cm2. The charge rate is 0.05 C. The electrolyte is PVDF powder / C2mpyrBF4 / LiFSI and the anode is Li metal. [Figure 12] (b) First galvanostatic charge-discharge cycling of Fe(BF4)26H2O / C2mpyrBF4 / LiFSI / graphene tested in a lithium cell at 50 °C with a cathode loading of 0.72 mg / cm2. (b) Corresponding cycle number-capacity curves over 100 cycles. The charge rates are 0.05 C from cycles 1 to 50 and 0.1 C from cycles 51 to 100. The electrolyte is PVDF powder / C2mpyrFSI / LiFSI and the anode is Li metal. [Figure 13] (b) First galvanostatic charge-discharge cycling of Fe(BF4)26H2O / C2mpyrBF4 / NaFSI / graphene tested in a sodium cell at 50 °C with a cathode loading of 0.8 mg / cm2. (b) Corresponding cycle number-capacity curves over 100 cycles. The charge rates are 0.05 C for cycles 1-5 and 0.1 C for cycles 6-100. The electrolyte is PVDF powder / C2mpyrFSI / / NaFSI and the anode is Na metal. [Figure 14] (a) First galvanostatic charge-discharge cycling of Fe(BF4)26H2O / CMC / LiFSI / graphene at 50 °C with a cathode loading of 0.6 mg / cm2. The charge rate is 0.05 C. The electrolyte is C3mpyrFSI / LiFSI (liquid) and the anode is Li metal. [Figure 15] The first three galvanostatic charge-discharge cycles of (a) CuF2 / C2mpyrBF4 / LiBF4 / graphene cathode (cathode loading 0.6 mg / cm2) and (b) CuF2 / PVDF / LiBF4 / graphene (cathode loading 1.1 mg / cm2). The cells were tested at 50 °C with a charge rate of 0.05 C. The electrolyte is PVDF film supported PDADAMA / C3mpyrFSI / LiFSI and the anode is Li metal. [Figure 16]The stable performance of Ni(PO3)2-PVDF-LiFSI-carbon (cathode loading 1 mg / cm2) and Ni(PO3)2-C2mpyrFSI-carbon (cathode loading 3 mg / cm2) at 50 °C for 100 cycles in the voltage range of 1-3.7 V. The charge rate is 0.05 C. The electrolyte is PVDF powder / C2mpyrFSI / LiFSI and the anode is Li metal. [Figure 17] FIG. 13 shows the cycling performance at a) C / 10, C / 5 and C / 2, and b) voltage profiles at C / 10 and C / 2 of Li|PILBLOC|LFP cells with different conductive binders cycled at 70° C. [Figure 18] Cycling performance (loading 0.22-0.28 mg / cm2, C / 50, 50°C) of (a) a [C2mpyr][FSI] composite anode using a [C2mpyr][FSI] PVDF fiber composite interlayer electrolyte with composition (wt%) Si:carbon black:Na-CMC:[C2mpyr][FSI]:LiFSI = 59.5:12.8:12.8:9.2:5.8, and (b) a Si anode using 1 M LiPF6 in EC-DMC (1:1 vol%) liquid electrolyte with composition (wt%) Si:carbon black:Na-CMC = 70:15:15. [Figure 19] The cycling performance of C / 20 and C / 10 LiFePO4 composite electrodes (LiFePO4 60 wt%, [C2mpyr][FSI] 25 wt%, C65 10 wt%, loading 1.1 mAh / cm2) at 50 °C using PILBLOC solid electrolyte membranes (LiFSI / PIL units 3 mol and C3mpyrFSI / PIL units 1.5 mol) is shown. [Figure 20] The cycling performance of LiFePO4 composite electrodes (LiFePO4 60wt%, [C2mpyr][FSI] 25wt%, C65 10wt%, loading 1.1mAh / cm2) at 50 °C with PILBLOC solid electrolyte membranes (LiFSI / PIL units 3mol and C3mpyrFSI / PIL units 1.5mol) is shown. [Figure 21]The cycling performance of a LiMn2O4 composite electrode (LiFePO4 60wt%, [C2mpyr][FSI] 25wt%, C65 10wt%, loading 1.1mAh / cm2) at 50 °C for C / 10 (first two cycles) and then 1C using a PILBLOC solid electrolyte membrane (LiFSI / PIL unit 3mol and C3mpyrFSI / PIL unit 1.5mol). [Figure 22] We show schematics of the preparation of a number of different Si-ionic binder electrodes that can be used to incorporate ionic binders into electrodes as (1) a coating on silicon particles, (2) a coating on conductive carbon (C65) particles, (3) a coating on both Si and C65 particles, and (4) drop casting of OIPC composites onto preformed electrodes or (Ref) a comparison with an electrode without a CMC binder, which has low peel strength. [Figure 23] FIG. 23 shows the cycling performance of electrodes prepared according to FIG. [Figure 24] Cycling performance of Si-OIPC composite anodes (Si loading 1.22–1.48 mg / cm2, utilizing polypropylene separator filled with Li-doped [P1222][FSI] electrolyte, charged at C / 10 and discharged at C / 50, 50 °C), where the OIPCs are (a) [C2mpyr][FSI], (b) [HMG][FSI], and (c) [P1222][FSI]. The composition of the Si-OIPC composite anode is Si:graphene:Na-CMC:citric acid:KOH:OIPC:LiFSI = w1:w2:w3:w4:w5:w6 wt%, with (w1:w2:w3:w4:w5:w6) = (61.5, 9.6, 6.0, 7.0, 0.8, 9.2, 5.9) for [C2mpyr][FSI], (61.6, 9.5, 6.1, 7.0, 0.8, 9.5, 5.5) for [HMG][FSI], and (61.4, 9.4, 6.0, 7.0, 0.8, 9.6, 5.7) for [P1222][FSI]. (d) shows the discharge capacity of each of the cells after 20 charge-discharge cycles. [Diagram 25]The discharge capacity of the Si-OIPC composite anode containing C2moxa after 15 charge-discharge cycles (charging at C / 10 and discharging at C / 50 at 50 °C using a polypropylene separator filled with 50:50 mol% Li-doped [C2mpyr][FSI] salt electrolyte). [Figure 26] The cycling performance of half-cells with Si electrodes using (1) [P1222][FSI]:LiFSI salt 50:50 mol% composite; (2) [C2mpyr][FSI]:LiFSI salt 50:50 mol% composite, and (3) [HMG][FSI]:LiFSI salt 50:50 mol% composite in half-cell configurations using PVDF, Solupor, or Celgard membrane separators filled with [P1222][FSI] composite is shown. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The inclusion of an organic ionic plastic crystal compound (OIPC) as a conductive, functional and / or ionic binder (or intimate OIPC complex with an ion transport salt) as a basic individual component of the electrode composition (collectively referred to herein as OIPC binder) has been found to favorably affect electrode performance, especially when the electrode is used in a solid electrode, particularly an all-solid-state energy storage device including a solid electrolyte. By complex, we mean an intimate dry mixture of OIPC and transport metal ion in a desired ratio, which is preformed separately and then added to the other components of the electrode composition to prepare the slurry used to form the electrode. Thus, when added to the electrode composition during formation, the OIPC / salt combination in complex form functions as a separate intimate ion-bound component, with the OIPC and salt in intimate association as a single component in the electrode composition. This is not the same as drop-casting OIPC in liquid monomer onto an already fabricated electrode, as performed by Ogawa 2019, Polymer 178 (2019) 121614. Desirably, the OIPC binders / composite binders described herein incorporate significant ionic conductivity into solid electrodes while advantageously providing advantageous additional performance benefits including one or more of the following: (i) improved mechanical properties of electrodes incorporating OIPC / OIPC composite binders due to the soft and plastic nature of OIPC; (ii) generation of target ion (e.g., Li, Na, Fe, etc.) conduction pathways in some cases by forming new highly ionically conductive new phases within the electrode composition with particularly favorable ionic conduction pathways; (iii) improved interfacial contact between (a) electrode / solid electrolyte and / or (b) electrode / current collector substrates, e.g., by SEI formation at the respective interfaces and / or improved adhesion resulting from the plastic nature of OIPC. The OIPC binder also improves one or more of the electrolyte / electrode interfacial contact and electrode / current collector interfacial contact and adhesion, e.g., by forming void-free contact between these components. This is a significant advance in the development of ASSBs and other ASS energy storage devices.Furthermore, the inclusion of OIPC in the electrode composition reduces the interfacial resistance, suggesting that the incorporation of OIPC / OIPC composites in electrodes can facilitate metal ion redox processes, such as the lithiation / delithiation processes in lithium devices.

[0018] A preferred embodiment of the present invention provides an all-solid-state energy storage device comprising at least one pair of positive and at least one negative electrodes, and an ion transport interlayer disposed between any of the pairs of electrodes, with separate portions of the interlayer in direct contact with a face of each electrode, each electrode being free of ion-conducting polymer electrolyte and comprising a dry electrode composition comprising particles of an electrochemically active material; particles of an optional electronically conductive additive; particles of an optional non-ionically conductive polymeric binder; and an internal ion binder in the form of a preformed complex of an organic ionic plastic crystal (OIPC) and a transport ion salt. Suitably, the contact between the ion transport interlayer and each electrode comprises a substantially void-free contact. Desirably, the voids between the particles are filled with the internal ion binder. Preferably, the ratio of OIPC to transport ion salt in the complex is about 9:1 to about 1:9 mol %, or about 9:1 to about 1:9 wt %, preferably about 1:1 mol % or about 1:1 wt %. Desirably, the internal ion binder is present in an amount of at least about 15 wt% and no more than about 50 wt% of the total electrode composition. Desirably, the dry electrode composition does not include organic solvents. More desirably, the composition ideally does not include one or more of organic solvents, non-OIPC ionic liquids, polymerizable ionic liquid monomers and / or polymerized poly(ionic liquids), ionogels, polyionic liquid ionogels, and / or polymerization initiators such as AIBN. Preferably, the ion transport interlayer is an ion transport membrane incorporating an ion transport salt, such as a solid electrolyte composite comprising an ion transport salt. Incorporation of the OIPC binder or OIPC composite binder of the present invention into the electrode not only promotes the creation of transport metal ion conduction pathways within the electrode and improves ionic conductivity within the inner portion / region of the electrode by filling the pores / voids within the electrode with OIPC / composite. Additionally, by promoting void-free contact between the solid electrolyte and the solid electrode, the quality of the electrolyte / electrode and electrode / current collector interfacial contact is improved, which further improves the electrical conductivity across the electrode / electrolyte interface. These effects improve the charge rate capability and cycle life of the electrodes when used in cells.

[0019] The inclusion of OIPC or OIPC complex as an ionic binder allows for the use of dry (e.g., liquid, organic solvent, gel or sol free) electrodes in energy storage devices, if desired. Advantageously, no liquid, ionically conductive polymer electrolyte, e.g., gel or sol electrolyte, is required in the electrode for device operation, leading to a significant increase in safety. Furthermore, in some embodiments, the electrode material including OIPC / OIPC binder is compacted or densified to provide reduced voids / increased void-free contact. Furthermore, the use of the improved electrodes described with solid electrolytes results in reduced voids (i.e., increased void-free contact) between the solid electrolyte and the active materials in the electrode. Given that more electrochemically active materials can be included in the electrode due to the improved ionic conductivity provided by the OIPC / OIPC complex, this makes the OIPC electrodes described herein particularly useful for ASSBs, as higher volumetric energy densities are possible in devices using the OIPC electrodes of the present invention provided. However, they can also be used in devices that rely on liquid electrolytes, if desired. Furthermore, when the OIPC electrodes described herein are used in devices, the overall amount of transport ion salt required to exhibit the same charge rate capability can also be reduced compared to a comparable liquid electrolyte system. This also improves the volumetric energy density of devices using OIPC electrodes. In some cases, OIPC provides new phases, e.g., liquid phases, inside the OIPC electrode, which are believed to be generated only during charge / discharge. Because transport ions can easily move through the liquid phase, the electrode requires less salt than a corresponding electrode that does not include an OIPC / OIPC complex. It is further believed that in some OIPC electrodes, new phases are formed that can solvate or otherwise incorporate the active material of the electrode complex in a manner that facilitates ion transport and / or charge transport of existing charge carriers.

[0020] Preferably, the OIPC complex of the present invention is preformed and added to the electrode composition as a preformed complex during electrode manufacture. Preferably, the OIPC complex of the present invention may comprise any useful amount of OIPC and ion transport salt, or OIPC and OMIEC polymer. For example, the ratio of OIPC in the complex may be any amount up to 97 wt% OIPC, with the remaining 3% or more being other salt components of the complex. In some embodiments, up to 95 wt% OIPC, up to 90 wt% OIPC, up to 85 wt% OIPC, up to 80 wt% OIPC, up to 75 wt% OIPC, up to 70 wt% OIPC, up to 65 wt% OIPC, up to 60 wt% OIPC, up to 55 wt% OIPC, up to 50 wt% OIPC, up to 45 wt% OIPC, up to 40 wt% OIPC, up to 35 wt% OIPC, up to 30 wt% OIPC, up to 25 wt% OIPC, up to 20 wt% OIPC, up to 15 wt% OIPC, up to 10 wt% OIPC, up to 5 wt% OIPC, up to 2.5 wt% OIPC, with the remainder being other salt components of the complex. Lower amounts of OIPC are typically preferred. In some embodiments, a 90 wt% OPIC complex is preferred, where the salt is 10 wt%. In other embodiments, a 50 wt% OIPC complex is preferred. The other component is preferably an ion transport salt, such as LiFSI or NaFSI. In other embodiments, the OMIEC polymer is PEDOT:PSS. In some embodiments, a 90 wt% OIPC:10 wt% PEDOTT:PSS complex is preferred. In other embodiments, a complex of 50 wt% or less OPIC:transport ion salt is preferred.

[0021] In other embodiments, the ratio of OIPC in the complex may be in an amount of 40 wt% or more OIPC, with the remainder being 60% or less of the other salt components of the complex. In some embodiments, amounts of 40 wt% or more OIPC, 55 wt% or more OIPC, 60 wt% or more OIPC, 75 wt% or more OIPC may be used. In particularly preferred embodiments, the complex contains 40 wt% to 60 wt% OIPC, with the remainder being ion transport salts. In preferred embodiments, the OIPC is present in the complex in an amount of 40 wt%, 41 wt%, 42 wt%, 43 wt%, 44 wt%, 45 wt%, 46 wt%, 47 wt%, 48 wt%, 49 wt%, 50 wt%, 51 wt%, 52 wt%, 54 wt%, 55 wt%, 56 wt%, 57 wt%, 58 wt%, 59 wt%, or 60 wt%, with the remainder being ion transport salt.

[0022] In particularly preferred embodiments, the complex comprises a molar ratio of OIPC to salt of 1:1.85 mol% to 1:0.5 mol% to 1:0.5 mol%. In some embodiments, the ratio of OIPC to salt is in the range of 1:1.5 mol% to 1:0.66 mol%. In some embodiments, the ratio of OIPC to salt is in the range of 1:1.22 mol% to 1:0.82 mol%. In some particularly preferred embodiments, the ratio of OIPC to salt is in the range of 1:1.25 mol% to 1:0.75 mol%, more preferably 1:1.15 mol% to 1:0.90 mol%. Most preferably, the ratio is about 1:1 mol% OIPC to ion transport salt, where about means ±5% ion transport salt.

[0023] Suitably, the preformed OIPC / transport ion salt complex is selected from the group consisting of OIPC and LiFSI; OIPC and LiFSI; or OIPC and LiFSI; or the cations BF4 and LiFSI; the cations FSI and LiFSI; or the cations TFSI and LiFSI, where "cation" is the OIPC cation, preferably CMPyrBF4 and LiFSI; CMPyrFSI and LiFSI; or CMPyrTFSI and LiFSI.

[0024] Desirably, the electrode comprises 50 wt% or less of the OIPC / ion transport salt complex as a fraction of the total electrode composition weight, particularly for graphite-based electrodes. In some embodiments, 45 wt% or less, 40 wt% or less, 35 wt% or less, 30 wt% or less, 25 wt% or less, 20 wt% or less, 15 wt% or less of the OIPC / ion transport salt complex is included. In some embodiments, a minimum of 10 wt% of the complex is included.

[0025] Desirably, the electrode comprises 15 wt%, 30 wt% or 50 wt% of the OIPC / ion transport salt complex as a fraction of the total electrode composition weight, particularly for graphite electrodes, and most preferably about 30 wt% for graphite electrodes.

[0026] Preferably, the complex is about a 1:1 mol% OIPC / transport ion salt complex, e.g., about a 1:1 mol% complex of [C2mpyr][BF4] and LiFSI, or about a 1:1 mol% complex of [C2mpyr][FSI] and LiFSI, although any ratio in the range of 1:1.85 mol% to 1:0.5 mol% to 1:0.5 mol% can be used.

[0027] In other embodiments, the complex is about a 1:1 wt% OIPC / transport ion salt complex, for example, about a 1:1 wt% complex of [C2mpyr][BF4] and LiFSI, or about a 1:1 wt% complex of [C2mpyr][FSI] and LiFSI, although any ratio ranging from 1:1.85 wt% to 1:0.5 wt% to 1:0.5 wt% can be used.

[0028] In other embodiments, it is believed that the active material remains as a separate phase within the OIPC / salt composite electrode. A preferred OIPC electrode includes a soft interphase that is interfacial with both the electrode and electrolyte structures of the solid-state device. It is believed that the interphase provides an ionically conductive bridge or other means for improving connectivity between the electrode composition and the solid-state electrolyte.

[0029] In preferred embodiments, a new class of organic-salt hybrid materials with new phases are obtained, which can reversibly incorporate counterions and support redox reactions, alloying or intercalation, thus enabling charge storage and achieving high energy, long life, and high safety performance. The presented data highlights multiple advantageous functions of the OIPC binder / OIPC composite binder in various electrode types, especially intercalation electrodes such as graphite anodes or layered metal oxide cathodes, conversion reaction material-based electrodes that contain redox couples as active materials, and alloy-type electrodes such as silicon. In some particularly preferred embodiments, the composites with the above mol% ratios described are particularly beneficial in alloyed or intercalated electrodes, such as graphite, hard carbon, silicon, phosphorus, selenium, antimony, bismuth, etc., especially alloyed or intercalated negative electrodes. In particular, the above mol% ratios, especially about 1:1 mol% ratios, are advantageous for alloyed electrodes such as silicon electrodes.

[0030] Indeed, a beneficial effect imparted by OIPC is the formation of cycling conversion reaction material-based electrodes, where such cycling of these materials is not possible in the absence of the OIPC / OIPC complex binder.

[0031] Thus, in one aspect, the present invention relates to an OIPC electrode, preferably for an all-solid-state energy storage device, comprising an electrode composition comprising at least one electroactive material and at least one internal ionic binder in the form of at least one organic ionic plastic crystal (OIPC) compound. Desirably, the OIPC is a non-polymeric OIPC compound. Desirably, the OIPC is not a monomeric OIPC compound, i.e., does not contain polymerizable functional groups, particularly vinyl or allyl groups, that form polyionic liquids (polymerized ionic liquids) in the electrode composition. Preferably, the composition does not contain ionic liquid ionogel, i.e., any form of polymerized ionic liquid. It is understood that the electrode may be pressed during manufacture, i.e., pressure may be applied to compact or densify the components in the electrode. Thus, the OIPC in the composition is compacted together with all other components present. This is in contrast to, for example, Owaga electrodes, where the ionogel is formed within a preformed electrode following electrode formation (e.g., casting and drying) by bulk polymerization of drop-cast ionic liquid monomers in the presence of an initiator such as AIBN.

[0032] Suitably, the electrochemically active material is in particulate form in the composition. Typically, the electronically conductive additive is also present in particulate form. Desirably, the OIPC or OPIC complex is homogeneously dispersed throughout the composition, or at least substantially dispersed. The surface of the electrode composition may have some undispersed OIPC grains, but in some embodiments, the entire electrode structure is homogeneous, as determined, for example, by elemental mapping and BSE imaging, which confirms high dispersion of the OIPC binder material / complex throughout the electrode.

[0033] Preferably, the electrode composition comprising the OIPC / OIPC composite is pressed or compacted or otherwise densified, for example into a 3D form with opposing faces, to reduce the porosity of the electrode. Preferably, a first face of the electrode composition is in electronic contact with a current collector, in particular an Al or Cu current collector. Preferably, the contact between the electrode and the current collector is substantially void-free. Preferably, another face of the electrode is in electronic contact with a solid electrolyte. Preferably, the contact between the electrode and the electrolyte is substantially void-free.

[0034] In some embodiments, the OIPC coats or substantially surrounds the electroactive material particles so as to contact or coat the active particles in a manner that firmly connects the active particles in the composition to each other. The OIPC complex may coat all or a portion of the electrode composition particle components. For example, the OIPC complex may coat only the electroactive material particles, only the conductive additive particles, or a combination of both the electroactive material particles and the conductive additive particles simultaneously. In these embodiments, preferably the OIPC complex is a 1:1.85 mol% to 1:0.5 mol% to 1:0.5 mol% OIPC to salt complex as described above, most preferably comprising [C2mpyr][NTf2] (P12NTf2) as the OIPC and LiNTf2 as the salt. In particular, about a 1:1 mol% complex as described above is used, most preferably comprising [C2mpyr][NTf2] (P12NTf2) as the OIPC and LiNTF2 as the salt.

[0035] Advantageously, the more OIPC present, the better the particles are coated. Furthermore, due to the tackiness or adhesiveness of OIPC, including more OIPC increases the bonding and adhesion / interface contact, reducing voids between the electrode composition and the current collector and / or solid electrolyte, leading to improved performance. The inventors are not aware of other dry electrode compositions that use OIPC with an ion transport salt as a composite for use as an inherent component of a formulated and cast electrode. Preferably, the OIPC is dispersed between and around the electroactive material particles and / or conductive particles, which can result in reduced contact resistance between the OIPC / OIPC composite and the electroactive material particles. In a preferred embodiment, the OIPC component forms a network of transport ion conduction pathways within the electrode. In the absence of the OIPC binder, the electrode does not have such transport ion conduction pathways, resulting in higher contact resistance between the particles of the electroactive material.

[0036] In some embodiments, the transport ion conductive pathway may be formed from multiple OIPC or OIPC composite grains or particles that contact each other, so that they are well connected to each other as well as to other components of the electrode composition, particularly the active material particles. Preferably, the OIPC or OIPC composite grains or particles fill most or substantially all of the voids or pores between the active material particles, providing an ion conductive pathway therebetween. When the OIPC / composite is compacted with other components, the effects described herein are amplified. In particularly preferred embodiments, the OIPC is believed to form new liquid phases (non-solvents or non-electrolytes) or other semi-solid phase regions within the solid electrode that can only be generated during charge / discharge, which act as particularly efficient and stable transport ion pathways / channels. Preferably, the transport ion conductive pathway contacts the solid electrolyte or intermediate layer on the first surface of the electrode. In this way, the soft and plastic nature of the OIPC, when also present in the ASSB, allows for much better interfacial contact between the first surface of the electrode and the solid electrolyte, thereby facilitating ion transport between the electrode and improving charge / discharge performance in the ASSB or other energy storage device. Incorporation of the OIPC / OIPC complex binder into the electrode is believed to reduce interfacial resistance and enhance redox processes in electrodes containing OIPC. Additionally, inclusion of the OIPC / OIPC complex binder in the electrode composition is believed to mitigate undesired reactions between the electrolyte and the active material. In some embodiments, the OIPC / OIPC complex improves the interfacial adhesion between the electrode surface layer and the solid electrolyte interlayer. Advantageously, the improved interfacial adhesion enhances ionic conductivity from the solid electrolyte to the electrode and from the electrode to the solid electrolyte in the ASSB. This addresses a key challenge of current solid-state devices.

[0037] Suitably, the OIPC / OIPC complex is well dispersed throughout the electrode composition, from the first side / surface of the electrode facing the electrolyte, through all the inner parts of the electrode composition, all the way to the second side / surface corresponding to the innermost boundary with the current collector. Preferred electrode compositions, particularly graphite electrode compositions, exhibit a morphology or characteristic upon SEM examination of their cross-section in which the active material particles at the surface of the first side (directed towards the solid electrolyte / interlayer in use) are more densely packed (e.g. adopt a horizontal arrangement with fewer interparticle voids / pores or a compacted arrangement) than at the second side (directed towards the current collector in use). The particles at the first side / surface have their basal planes facing towards the intermediate layer. In contrast, the active material particles in the inner region (located away from the first and second sides / surfaces) are more randomly oriented with larger or more enlarged interparticle voids due to the nature of the packing, particularly in the case of graphite.

[0038] Preferably, most of the voids between the particles are completely or partially filled with a concentrated portion of the intimate OIPC / OIPC:ion transport salt complex. Thus, the intimate material ionically connects particles that would otherwise not be ionically connected or poorly ionically connected. Furthermore, the presence of the intimate material reduces the interfacial resistance between the particles. Overall, the presence of the OIPC / OIPC complex improves ion flow through the dry electrode. Performance is improved, and in some cases approaches that of a comparable system using a liquid electrolyte. In some cases, a portion of the internal particles are aligned vertically to the current collector. This is believed to result in particularly efficient insertion and extraction of target ions, at least for intercalation electrodes. This morphology is particularly desirable when the electrode is a graphite electrode and the electroactive material is in the form of graphite particles. At least for graphite anodes, the inventors believe that a higher fraction (i.e., higher density) of horizontally oriented active particles tends to slow down ion conduction, while a random orientation of the internal active material particles favors ion conduction.

[0039] Transport ion salt - Preferably, the transport ion salt is an inorganic metal salt typically used in energy storage devices. Preferably, the transport ion salt is one or more of alkali metal, alkaline earth, or transition metal salts. Preferred ion salts include Li, Na, K, Ca, Al, Mg, and Zn salts. Preferably, the anions for these salts include bis(trifluoromethanesulfonyl)imide, TFSI; bis(fluorosulfonyl)imide, FSI; fluorosulfonyl(trifluoromethanesulfonyl)imide, FTFSI; trifluoromethanesulfonate; tetrafluoroborate, BF4; perfluorobutanesulfonate, PFBS; hexafluorophosphate, PF6; tetracyanoborate, B(CN)4; dicyanamide, DCA; thiocyanate, SCN; cyclic perfluorosulfonylamide, CPFSA, and carborane.

[0040] Desirably, the ionic salt is a lithium salt selected from the group consisting of, for example, lithium tetrafluoroborate (LiBF), lithium bis(trifluoromethanesulfonyl)imide (Li[TFSI]), lithium bis(fluorosulfonyl)imide (Li[FSI]), lithium trifluoromethanesulfonate (Li[OTf]), lithium perchlorate (LiClO), lithium dicyanamide (LiDCA), lithium cyanate (LiOCN), lithium thiocyanate (LiSCN), lithium bis[(pentafluoroethyl)sulfonyl]imide, lithium 2,2,2-trifluoromethylsulfonyl-N-cyanoamide (TFSAM), lithium 2,2,2-trifluoro-N-(trifluoromethylsulfonyl)acetamide (TSAC), lithium nonafluorobutanesulfonate (NF), lithium carborane, lithium difluoro(oxolato)borate, and combinations thereof. Preferably, the salt is a Li salt, for example LiTFSI.

[0041] Desirably, the ionic salt is a sodium salt selected from the group consisting of, for example, sodium tetrafluoroborate (NaBF4), sodium bis(trifluoromethanesulfonyl)imide (Na[TFSI]), sodium bis(fluorosulfonyl)imide (Na[FSI]), sodium trifluoromethanesulfonate (Na[OTf]), sodium perchlorate (NaClO4), sodium dicyanamide (NaDCA), sodium cyanate (NaOCN), sodium thiocyanate (NaSCN), lithium bis[(pentafluoroethyl)sulfonyl]imide, sodium 2,2,2-trifluoromethylsulfonyl-N-cyanoamide (TFSAM), sodium 2,2,2-trifluoro-N-(trifluoromethylsulfonyl)acetamide (NaTSAC), lithium nonafluorobutanesulfonate (NaNF), sodium carborane, sodium difluoro(oxolato)borate, and combinations thereof. Particularly preferred Na salts include sodium bis(trifluoromethanesulfonyl)imide (Na[TFSI]), sodium bis(fluorosulfonyl)imide (Na[FSI]), sodium triflate (NaOTf), sodium perchlorate (NaClO4), sodium dicyanamide (NaDCA), sodium cyanate (NaOCN), sodium tetrafluoroborate (NaBF4), sodium hexafluorophosphate (NaPF6), and combinations thereof. Preferred ion transport salts are inorganic metal salts for energy storage devices, such as inorganic lithium or sodium salts. Preferably, the ion transport salt has an anion selected from the group consisting of BF4, TFSI, FSI, and OTf. Suitably, preferred ion transport salts are selected from LiFSI, LiBF4, LiTFSI, LiOTf, NaFSI, NaBF4, NaTSI, NaTFSI, or NaOTf.

[0042] Conductivity enhancing additives - Preferred electrodes include one or more conductivity enhancing additives such as conductive carbon-based materials including carbon nanomaterials including carbon nanotubes, carbon fibers, mixed ionic-electronic conductors, and carbonaceous materials such as combinations thereof. However, when an OIPC binder in the form of a mixed ionic-electronic conductive polymer (MIEC) is used, the ionic and electronic conductivity of the binder may be high enough so that no other conductivity enhancing additives are required. In such cases, a carbon-free electrode may be formed. Suitably, the OIPC / MIEC polymer binder composite is an OIPC / PEDOT:PSS binder composite. Preferably, the mixed ionic electronic conductive polymer (MIEC) is PEDOT:PSS in a ratio of 50:50 to 95:5 PEDOT:PSS / OIPC, preferably PEDOT:PSS / OIPC in a ratio of 60:40 to 85:15, preferably PEDOT:PSS / OIPC in a ratio of 80:20 PEDOT:PSS / C2mpyrFSI in a ratio of 80:20.

[0043] Polymeric Binder - In some embodiments, preferred electrodes include one or more polymeric (non-ionically conductive polymeric material) binders, such as carboxymethyl cellulose (CMC), polyvinylidene fluoride PVdF, styrene butadiene rubber (SBR), polyacrylic acid (PAA), polyethylene (PE), polypropylene (PP), polyurethane (PU), polytetrafluoroethylene (PTFE), Nafion, and combinations thereof.

[0044] Electrode Materials - Preferred electrodes include electroactive materials for the cathode (positive electrode) or anode (negative electrode). In a cell, the electrode with a higher reduction potential is more susceptible to reduction and corresponds to the cathode (positive electrode material) of the cell where reduction occurs. Similarly, the anode (negative electrode material) is the electrode with a lower reduction potential. Materials are described herein as typical cathode or anode materials, but it is understood that the correct terminology will depend on any particular cell configuration being used.

[0045] Examples of materials that a typical negative electrode may include (or be made from) include graphite, particularly expanded graphite, hard carbon (non-graphitizable carbon), low potential transition metal oxides and phosphates, such as NASICON-type NaTi2(PO4)3 vanadates, vanadium layered oxides (e.g., O3NaVO2 and P2Na 0.7 VO2), titanates, e.g. Na2Ti3O7, NaTi3O6(OH).2H2O, Na2Ti6O 13 , TiNb2O7, Na 0.66 Li 0.22 Ti 0.78 O2, Na 0.6 Ni 0.3 Ti 0.7O2, and titanate / carbon black composites, alloying materials such as antimony, tin, phosphorus and combinations thereof (e.g., Sn-Sb alloys), tin-based composites such as tin powder / resins (e.g., polyacrylates), microcrystalline antimony-based composites such as microcrystalline antimony-black carbon electrodes, amorphous phosphorus, sodium (including sodium or lithium metal), and combinations thereof. In some embodiments, the negative electrode comprises sodium or lithium or iron. In some embodiments, the electrode is an anode, and the electroactive material is selected from hard carbon, graphite; silicon; lithium alloys such as lithium titanate, especially lithium titanium oxide; or metallic anode materials such as lithium metal and sodium metal. In other embodiments, the negative electrode consists essentially of sodium or lithium. In still other embodiments, the negative electrode comprises sodium metal or lithium metal. Other examples of materials that the negative electrode may comprise (or be made from) include those disclosed in The Emerging Chemistry of Sodium Ion Batteries for Electrochemical Energy Storage, Angewandte Chemie Int. Ed. 2015, volume 54, pages 3431; Na-ion batteries, recent advances and present challenges to become low cost energy storage systems, Energy & Environmental Science 2012, volume 5, page 5884; Energy Storage Materials Synthesized from Ionic Liquids Angewandte Chemie Int. Ed. 2014, volume 53, page 13342; Chemical Review 2014, volume 114, page 11636, the contents of which are incorporated herein in their entireties.For example, electroactive materials for a typical cathode or positive electrode may be selected from the group consisting of transition metal oxides; spinel materials, transition metal polyanionic compounds; sulfur; and conversion reaction materials that contain redox centers.

[0046] Preferably, the cathode material comprises a transition metal material selected from the group consisting of lithium cobalt oxide (LCO), lithium iron phosphate (LFP), lithium manganese phosphate (LMP), lithium nickel manganese cobalt oxide (NMC), and lithium nickel cobalt oxide doped with alumina (NCA), lithium manganese oxide (LMO). LFP is an example of a polyanionic compound, while LCO, LMO, etc. are layered oxide intercalation materials.

[0047] Suitable conversion reaction electroactive materials containing redox centers preferably include transition metal ion-based redox couples. A preferred such transition metal ion-based redox couple is Fe 2+ / Fe 3+ , Co 2+ / Co 3+ , Ni 2+ / Ni 3+ , Mn 2+ / Mn 3+ or Cu 2+ / Cu 3+ Preferably, the preferred conversion reaction material containing a redox center is Fe(BF4) 6H2O. 2+ / Fe 3+ , or Co from cobalt TFSI or Fe(II) triflate 2+ / Co 3+ Other suitable conversion materials include Ni(PO3)2. Other examples of conversion materials can be found in Energy Environ. Sci., 2017, 10, 435-459 and ACS Omega 2018, 3, 4591-4601, the relevant contents of which are incorporated herein by reference. For example, useful conversion electrode materials include transition metal oxides, transition metal chalcogenides (sulfides and selenides), phosphides, hydrides, and MS xAmong the various conversion electrodes, however, transition metal oxides are the most well known, including binary and ternary oxides of the 3d transition metals, such as Cr, Mn, Fe, Co, Ni, and Cu, as well as the 4d transition metals, including Nb and Mo. a X b Transition metal compounds with different anion species with X=F, O, S, P and H can support the insertion of metal ions (e.g., Li+ / Na+) through reversible conversion reactions. Some examples include Fe2O3, Co3O4, Mn3O4, FeS2, CoS2, MoS2, FeP, NiP2, and ternary oxides.

[0048] Examples of materials that the positive electrode may include (or be made from) include layered transition metal oxides (AMO2 type, including solid solutions of NaCoO2, NaFeO2, NaMnO2, NaNiO2). These are typically named O3 (ABCABC stacking), P2 (ABBA stacking) and P3 (ABBCCA stacking), with Na' in either a prismatic (i.e. P) or octahedral (i.e. O) coordination environment. These are called P2-Na 0.66 Co 0.66 Mn 0.33O2. Sodium polyanion materials can also be used as cathode materials, including olivine-type NaFePO4, fluorophosphates and pyrophosphates, Nasicon-type phases of the general formula Na5M5(XO2)4 (where M=transition metal and X=P, S), Na3V(PO4)F, fluorosulfates and sulfates (e.g. NaF5SO4F, and NaM(SO4)·4H2O (M=Mg, Fe, Co, Ni)), ferrophosphates (e.g. Na5FePO4) and silicates. Prussian blue analogues have also been used as cathodes (i.e., Na, M[Mp(CN)], ·zH0-M, and Mg are transition metals and hexacyanometallate vacancies exist). Other examples of materials that the negative or positive electrodes may include (or be made from) include those disclosed in Angew. Chem. Int. Ed. Engl. 2018, 57, 102; and Adv. Energy Mater. 2018, 8, 1703137.

[0049] OIPC - Organic ionic plastic crystals (OIPCs) can be divided into protic and aprotic classes depending on the availability of dissociable protons on the cation and / or anion. Protic OIPCs typically exhibit non-negligible vapor pressures, and some are distillable media with boiling points below their decomposition temperatures. Recently, more families of OIPCs have been discovered, including novel OIPCs containing pyrrolidinium, imidazolium, phosphonium, and metallocenium cations combined with various anions such as tetracyanoborates, tetrahalogenoferrates(III), camphorsulfonates, and nonafluorobutanesulfonates.

[0050] One characteristic of OIPCs may include at least thermal phase behavior, including one or more solid-solid phase transitions prior to melting (pre-melting or partial melting solid-solid phase transitions). Techniques for measuring and characterizing solid-solid phase transitions of OIPCs include differential scanning calorimetry (DSC), whereby the solid-solid phase transitions are characterized by DSC plots where a discontinuity (e.g., spike) in heat flow is observed in the partial melting temperature range in addition to and distinct from the discontinuity resulting from the solid-liquid (melting) transition of the OIPC. Another characteristic of molecular disorder in the solid state is determined from static solid-state NMR, whereby plastic OIPCs exhibit one or more NMR linewidths of 20 KHz or less. Desirably, the linewidths become even narrower with increasing temperature. Desirably, the NMR linewidths are 10 KHz or less, preferably 5 KHz or less, and in some embodiments 1 KHz or less. Another characteristic of molecular disorder in the solid state is determined by observation of microstructure / morphology by SEM analysis. Features include the observation of multiple grains with different orientations, the observation of slip and sliding planes in SEM analysis, the collection of slip planes within different grains, and the observation of grain boundaries from fracture surfaces of the material. Further evidence of plasticity increases with increasing temperature. Another feature is that at about 60 JK -1 Mol -1 less than, more preferably about 50 JK -1 Mol -1 less than, more preferably about 40JK -1 Mol -1 less than, more preferably about 30 JK -1 Mol -1 less than, more preferably about 20 JK -1 Mol -1 Entropy of melting less than ΔS f Other useful studies include X-ray diffraction, Raman spectroscopy, synchrotron X-ray diffraction, and molecular modeling such as molecular dynamics (MD), or a combination thereof.

[0051] Preferred OIPC compounds are plastic solids at the application operating temperature, for example, from about -100°C to about 200°C, from about -50°C to about 100°C, and most preferably from about -10°C to about 80°C. Particularly preferred compounds are plastic solids at least at room temperature. By "room temperature" is meant a temperature of from about 20°C to about 25°C, preferably 25°C. Preferred OIPC compounds have a melting point ≥ 60°C, ≥ 70°C, ≥ 80°C, ≥ 80°C, ≥ 100°C, ≥ 150°C, ≥ 200°C or ≥ 250°C. Preferred compounds exhibit plastic behavior at temperatures of from about -100°C to about 100°C. By "melting point" is meant the extrapolated onset temperature associated with the phase transition in melting from solid to liquid, as determined by differential scanning calorimetry (DSC). If a compound exhibits plasticity at very low temperatures, for example < 0°C, this typically indicates that the compound is advantageously highly disordered at room temperature.

[0052] Formation / Identification of OIPCs - OIPCs can be provided starting with at least one cation and at least one anion, the combination of cation and anion being a plastic crystal where the compound exhibits molecular disorder (and thus plasticity) that can be observed from characteristic features in, for example, two or more of thermal, solid state NMR and SEM studies, with no particular limitation on the type of cation and associated counter anion that can be utilized.

[0053] In preferred OIPC compounds, at least one of the positive functional groups of the OIPC is derived from a small cationic moiety such as an optionally substituted saturated or unsaturated heterocyclic ring, for example, pyrrolidine, morpholinium, oxazolidinium, piperidinium, thiolane, benzotriazole, or tetrahydrofuran. Desirably, at least one of the negative functional groups of the preferred OIPC is derived from a charge-delocalized anionic group, such as fluoroborate, oxalatoborate, sulfonylimide, fluorosulfonylimide (FSI), bis(trifluoromethanesulfonyl)imide (TFSI), etc. Substituents include methyl, ethyl, or propyl substituents.

[0054] Some suitable cations may be dications or trications. Preferred cations are symmetric. In some embodiments, the cation is a chiral cation. Examples of suitable cations include pyrrolidinium, imidazolium, oxazolidinium, phosphonium, and metallocenium cations, which are unsubstituted or C 1~6 It may be substituted with one or more functional groups selected from alkyl, preferably methyl, ethyl or propyl, CN, OMe, OEt and CN.

[0055] Preferably, one or more of the positively charged functional groups is C n (N 2,2,m )2 (where n=2, 3, 4, 6 and m=1, 2, 3, 4, 6);N 2,1,1,1 ;N 2,2,1,1 ;N 2,2,2,1 ;N 2,3,3,3 ;N 2,2,3,3 ;N 2,2,2,3 ;N 4,4,4,4 ;P 1,2,2,2 ;N 1,2,3,i3 ;N 2,2,2,2 ;N 3,3,3,3 and C2epyr, particularly aprotic cations. Cations capable of rotational motion (e.g., tetramethylammonium) are particularly desirable. Preferred cations include the C2mpyr cation, as well as C2epyr, C2moxa, phosphonium cations, [N 2(20202)3 ] + , [P 122i4 ] + , [P1(DEA)3] + Examples include:

[0056] Desirably, at least one of the positively charged functional groups having at least one positive charge is derived from an ammonium cation, a phosphonium cation, or a sulfonium cation, which contain positively charged nitrogen, positively charged phosphorus, and positively charged sulfur, respectively.

[0057] Desirably, the at least one positively charged functional group is derived from a nitrogen-containing, positively charged ammonium cation. A preferred ammonium cation has the general formula [NR 4 R 3 R 2 R 1 ] + Desirably, the at least one positively charged functional group is derived from a sulfonium cation that contains sulfur and has a positive charge. A preferred sulfonium cation has the general formula [SR 3 R 2 R 1 ] + Preferably, the at least one positively charged functional group having at least one positive charge is derived from a phosphorus-containing, positively charged phosphonium cation. A preferred phosphonium cation has the general formula [PR 4 R 3 R 2 R 1 ] + In each of the above cases, R 1 ~R 4 may be the same or different and may be independently selected from optionally substituted alkyl and optionally substituted aryl, or one R group is selected from optionally substituted alkyl and optionally substituted aryl, and the remaining two R groups together with P form an optionally substituted heterocyclic ring, and R 1 is selected from H, optionally substituted alkyl and optionally substituted aryl. Examples of suitable phosphonium cations include tetra(C 1~20 Alkyl)phosphonium, tri(C 1~9 Alkyl)mono(C 10~20 Alkyl)phosphonium, tetra(C 6~24 aryl)phosphonium, phosphoranium, phosphinanium and phosphorinanium.

[0058] Desirably, at least one of the positively charged functional groups having at least one positive charge is derived from a morpholinium cation, a pyrrolidinium cation, or an imidazolium, each of which includes a nitrogen having a positive charge. The ring of the pyrrolidinium cation or the imidazolium may be unsubstituted or R 1 and R 2 In each case, R 1 and R 2 may be the same or different and may be independently selected from optionally substituted alkyl and optionally substituted aryl, or one R group is selected from optionally substituted alkyl and optionally substituted aryl, and the remaining two R groups together with P form an optionally substituted heterocyclic ring, and R 1 is selected from H, optionally substituted alkyl, and optionally substituted aryl.

[0059] Other preferred cations include dialkylpyrrolidinium, pyrrolidinium, monoalkylpyrrolidinium, dialkylimidazolium, monoalkylammonium, imidazolium, tetraalkylammonium, quaternary ammonium, trialkylammonium, dialkylammonium, dialkylammonium, dialkanolalkylammonium, alkanoldialkylammonium, bis(alkylimidazolium), bis(dialkyl)ammonium, bis(trialkyl)ammonium, diallylammonium, dialkanolammonium, and alkylalkanolammonium. Examples of suitable ammonium salts include ammonium salts of alkyl aryl ammonium salts, ...

[0060] Examples of OIPC cations and anions that can be used as a starting point for the design of the OIPC compounds of the present invention can be found in Trends in Chemistry, April 2019, Vol. 1, No. 1; J. Mater. Chem., 2010, 20, 2056-2062, and Phys. Chem. Chem. Phys., 2013, 15, 1339 (particularly Figures 1, 2, 3 and Table 1), the entire contents of which describing cations and anions and OIPCs are incorporated herein by reference. Preferred examples of known OIPCs include [N 1,1,1,1 ][DCA], [C2mpyr][FSI], [C2mpyr][BF4], [P 1,2,2,2 ][FSI], [P 1,2,2,i4 ][PF6], [P 1,4,4,4 ][FSI], [H2im][Tf], [Hmim][Tf], [N 2,2,3,3 [BBu4], [N3,3,3,3 [BF4], [C2epyr][TFSI], [C2epyr][FSI], [C2epyr][PF6], [C2epyr][BF4], [C1mpyr][(FH)2F] and [C2mpyr][(FH)2F], [C4mpyr][TFSI], [(NH2)3][Tf], [2-Me-im][Tf] and [TAZm][PFBS].

[0061] Anion Component - Suitably, at least one of the negatively charged functional groups having at least one negative charge may be derived from an anion from a known OIPC. Some preferred anions may be protic or aprotic anions, depending on the availability of labile protons. Some preferred anions may be dianions or trianions. Some preferred anions may be symmetric. Some preferred anions may be chiral.

[0062] Preferred anions may have a "spherical" structure, whereby the anion has a configuration that exhibits spherical symmetry about its center upon rotation about an axis. Additional anions may have diffusible or mobile negative charges that can be present or averaged across the anion structure when tethered in an OIPC compound.

[0063] Preferably, one or more of the negatively charged functional groups are Tf, (FH) n Anions may be selected from the group of anions consisting of F (where 1≦n≦3), and TFSI, particularly aprotic anions. Other suitable anions for forming one or more of the negatively charged functional groups may be selected from the group of anions consisting of I, Br, PF6, TFSI, BBu4, CrO3Cl, CrO3Br, BF4, FTFSI, DCA, FSI, and Tf. Centrosymmetric anions (e.g., hexafluorophosphate and tetrafluoroborate) are particularly preferred.

[0064] At least one negative charge (F -The preferred at least one negatively charged functional group is BF4 - , PF6 - , N(CN)2, (CF3SO2)2N - , (FSO2)2N - , OCN, SCN - , dicyanomethanide, carbamoylcyano(nitroso)methanide, (C2F5SO2)2N - , (CF3SO2)3C, C(CN)3 - , B(CN)4 - , (C2F5)3PF3 - , alkyl-SO3 - , Perfluoroalkyl-SO3 - , Aryl-SO3 - , I - , H2P04 - , HPO4 2- , sulfate, sulfite, nitrate, trifluoromethanesulfonate, p-toluenesulfonate, bis(oxalate)borate, acetate, formate, gallate, glycolate, BF3(CN) - , BF2(CN)2 - , BF(CN)3 - , BF3(R) - , BF2(R)2 - , BF(R)3 - (where R is an alkyl group (e.g., methyl, ethyl, propyl)), cyclic sulfonylamide, bis(salicylate)borate, perfluoroalkyltrifluoroborate, chloride, bromide, and transition metal complex anions (e.g., [Tb(hexafluoroacetylacetonate)4]). Preferably, the anion is, for example, BF4 - , PF6 - , (CF3SO2)2N - , (FSO2)2N - , BF3(CN) - , BF2(CN)2 - , BF(CN)3 - , BF3(R) - , BF2(R)2 - , BF(R)3 -(wherein R is an alkyl group (e.g., methyl, ethyl, propyl, butyl)), (C2F5SO2)2N - , (C2F5)PF3 - , (C2F5PO2)2N, (CF3SO2)NCN, (CF3SO2)N(SO2F), (CF3CO)N(SO2F) and perfluoroalkyl-SO3 - The other anion is a fluorinated anion selected from the group consisting of [B(tfe)]4 - and [B(hfip)4] - It is.

[0065] OIPC - Examples of known OIPCs are N,N-methylethylpyrrolidinium tetrafluoroborate, N,N-methylpropylpyrrolidinium tetrafluoroborate, dimethylpyrrolidinium tetrafluoroborate, dimethylpyrrolidinium thiocyanate, N,N-ethylmethylpyrrolidinium thiocyanate, tetramethylammonium dicyanamide, tetraethylammonium dicyanamide, N,N-methylethylpyrrolidinium bis(trifluoromethanesulfonyl)amide, diethyl(methyl)isobutyl)phosphonium bis(fluorosulfonyl)amide, diethyl(methyl)isobutyl)phosphonium tetrafluoroborate, diethyl(methyl)isobutyl)phosphonium hexafluorophosphate, methyl(triethyl)phosphonium bis(fluorosulfonyl)amide, methyl(triethyl)phosphonium bis(trifluoromethylsulfonyl)amide, triisobutyl(methyl)phosphonium hexafluorophosphate, triisobutyl(methyl)phosphonium bis(fluorosulfonyl)amide ... and combinations thereof.

[0066] As used herein, an organic ionic plastic crystal (OIPC) compound is one that contains at least one cation and at least one anion and exhibits molecular disorder in the solid state. An OIPC compound can be formed and / or identified by a method comprising the steps of: (i) providing a compound to be screened for OIPC behavior, the compound comprising at least one positively charged functional group having at least one positive charge and at least one negative functional group having at least one negative charge; (ii) determining that a compound is an organic ionic plastic crystal (OIPC) compound by screening the compound for evidence of molecular disorder in the solid state, identifying the compound as an organic ionic plastic crystal (OIPC) compound, the molecular disorder being evidenced by the compound exhibiting two or more, preferably three or more, more preferably all of the following: - Thermal phase behavior including one or more solid-solid phase transitions prior to melting; - in a static solid-state NMR spectrum, one or more NMR linewidths of 20 KHz or less; and - Microstructure or morphology including slip and sliding planes in SEM analysis. Desirably, the NMR line width is 10 KHz or less, preferably 5 KHz or less, and in some embodiments 1 KHz or less; - at least 10 when in the partially molten phase at the applied operating temperature (e.g., 50°C) as determined by electrochemical impedance spectroscopy (EIS); -4 S / cm, more preferably at least 10 -3 S / cm. In the context of organic ionic plastic crystals, they have an ionic conductivity of at least 10 when in the partially molten phase. -4 S / cm, more preferably at least 10 -3The expression ionic conductivity in S / cm refers to the value of ionic conductivity determined by electrochemical impedance spectroscopy (EIS) according to the following procedure. First, the OIPC is formed into 30 pellets (nominal thickness 1 mm, diameter 13 mm) under dry conditions, then sandwiched and sealed between two stainless steel blocking electrodes fixed together. The ionic conductivity is measured by EIS using a frequency response analyzer driven by impedance measurement software (available to those skilled in the art). Data is collected in the frequency range of 10 MHz to 0.1 Hz at temperatures where the OIPC is solid and in the partially molten phase. The temperature of the cell is controlled using a high-precision temperature controller (accuracy is better than ±1°C) and the temperature is measured using a thermocouple in close proximity to the blocking electrodes. The sample is heated (typically 0.5°C / min) and allowed to thermally equilibrate (typically for 5-20 min) before the impedance is measured at each temperature point. For the avoidance of doubt, those skilled in the art can practically devise appropriate conditions of heating rate and duration of thermal equilibration <10 based on the physical consistency of the sample material. For example, an OIPC of soft consistency undergoing wire-based EIS measurements, where the amount of sample is much larger, will require a longer thermal equilibration step (e.g., up to 20 min), whereas an OIPC of stiffer consistency undergoing plate-based EIS measurements, where the amount of material is smaller, will suffice with a shorter thermal equilibration step (down to 5 min).

[0067] The solid-solid phase transition of an OIPC can be determined using differential scanning calorimetry (DSC), which is usually performed by linearly scanning the sample temperature through a range of values, making it possible to obtain a plot of the heat flow into or out of the OIPC relative to a reference sample. From this, the heat capacity, transition temperature, transition enthalpy and entropy, as well as the melting point, can also be determined. Generally, in a DSC plot, the phase transition of the material can be visualized in the form of a discontinuity in the heat flow relative to a reference at a particular temperature, for example in the form of a spike in the heat flow signal. In many cases, the solid-solid phase transition of an OIPC is characterized by a DSC plot in which a discontinuity (e.g., a spike) in the heat flow in the partial melting temperature range is observed. For the avoidance of doubt, such discontinuities are in addition to and distinct from the discontinuities resulting from the solid-liquid transition (i.e., melting) of the OIPC. For a given combination of cation and counteranion, (i) it contains at least one cation and at least one counteranion, (ii) it is plastically crystalline, and (iii) it has a melting point of at least 10 when in its partially molten phase. -4 There is no particular restriction on the type of cation and associated counter anion that can be utilized, provided that an OIPC with an ionic conductivity of S / cm is obtained.

[0068] Preferred OIPCs contain at least one cation selected from the group consisting of pyrrolidinium, imidazolium, phosphonium, guanidinium, oxazolidinium and metallocenium cations. Desirably, preferred OIPCs contain at least one anion selected from the group consisting of tetrafluoroborate, FSI, TFSI, tetracyanoborate, tetrahalogenoferrate(III), camphorsulfonate, hexafluorophosphate, triflate and nonafluorobutanesulfonate (nonaflate). Suitably, the OIPC may be selected from [C2mpyr][BF4], [C2mpyr][FSI], [C2mpyr][TFSI]. OIPC[C2mpyr][FSI] or [C2mpyr][BF4] are particularly preferred. Suitably, the OIPC is provided as an OIPC / transport ion salt complex as described above. In such cases, the ion transport salt is preferably as described herein.

[0069] Electrode Composition - A preferred electrode composition comprises the following components: an electroactive material; optionally at least one conductivity enhancing additive; optionally at least one non-ionically conductive polymeric binder; at least one OIPC; and at least one transport ion salt.

[0070] More preferably, the electrode composition comprises the following components in the recited amounts: about 40 wt% to about 96 wt% electroactive material; optionally, up to about 25 wt% of at least one conductivity enhancing additive; optionally, up to about 15 wt% of at least one polymeric binder; and about 0.5 wt% to about 60 wt% of the OIPC / transport ion salt complex.

[0071] Preferably, the dry electrode comprises 15 wt%, 30 wt% or 50 wt% of the OIPC / ion transport salt complex. Preferably, the mol% ratio or wt% of the components in the complex is about 1:1 OIPC / ion transport salt complex, such as about 1:1 [C2mpyr][BF4] and LiFSI, or about 1:1 [C2mpyr][FSI] and LiFSI. Preferably, the electroactive material is graphite, hard carbon, transition metal salt, silicon, phosphorus, selenium, bismuth, antimony, or transition metal oxide, or a polyanionic layered material.

[0072] Suitably, the preferred electrode comprises about 40 wt% to about 96 wt% graphite; optionally up to about 25 wt% carbon black; optionally up to about 15 wt% Na-CMC; and about 0.5 wt% to about 60 wt% of a composite of [Cmpyr][FSI] and LiFSI.

[0073] Suitably, the preferred electrode comprises about 20 wt % to about 96 wt % of the reversible redox couple material; about 2 wt % to about 20 wt % of the graphene; and about 0.5 wt % to about 60 wt % of the OIPC / transport ion salt complex.

[0074] Desirably, the reversible redox couple material is derived from a transition metal salt selected from the group consisting of Fe(BF4) salts; copper fluoride, preferably CuF2; cobalt fluoride, preferably CoF3; cobalt chloride, preferably CoCl2·6H2O; and iron chloride, preferably FeCl3.

[0075] Suitably, in some embodiments, one or more new material phases are formed in the electroactive material. Preferred transition metal salts are Fe(BF4)2·6H2O, Co(II)TFSI, Fe(II) triflate or Ni(PO3)2. One preferred electrode contains 76 wt% Fe(BF4)2·6H2O; 10 wt% graphene; and 14 wt% of about 1:1 mol% C2mpyrBF4 and LiFSI. Other preferred electrodes contain LiFePO4 or LiMn2O4.

[0076] For example, in one embodiment, a desirable electrode comprises about 60 wt% LiFePO4, about 28 wt% PEDOT:PSS, about 7 wt% C2mpyrFSI, and about 5 wt% LiFSI.Suitably, another preferred electrode comprises about 60 wt% LiFePO4, about 30 wt% [C2mpyr][FSI], about 5 wt% PVDF, and about 5 wt% carbon.

[0077] In one embodiment, a preferred electrode is in the form of a silicon anode comprising about 50 wt% to about 75 wt% silicon; optionally up to about 15 wt% of at least one conductivity enhancing additive; optionally up to about 15 wt% of at least one polymeric binder; and about 0.5 wt% to about 60 wt% of at least one OIPC / transport ion salt complex.

[0078] Desirably, the OPIC / transport ion salt complex may be selected from the group consisting of C2mpyrBF4 and LiFSI; C2mpyrFSI and LiFSI; or C2mpyrTFSI and LiFSI.

[0079] A preferred electrode comprises about 50wt%-90wt% silicon, preferably about 70wt%-88wt% silicon, most preferably the balance OIPC:salt, preferably a 50:50 mol% ratio.

[0080] A preferred electrode comprises about 59.5 wt% silicon; about 12.8 wt% carbon black; about 12.8 wt% Na-CMC; about 9.1 wt% of at least one OIPC; and about 5.8 wt% of at least one transport ion salt.

[0081] Preferred electrodes comprise [C2mpyr][FSI], [C2mpyr][BF4], [P1222][FSI], [HMG][FSI]OIPC, preferably in a 50:50 mol % combination with an ion transport salt, most preferably LiFSI or NaFSI. These are particularly suitable for use in all-solid-state devices using an interlayer, e.g., a membrane comprising an OIPC composite or a composite of, e.g., a PVDF, Solupor or Celgard membrane separator loaded with an [P1222][FSI] composite.

[0082] Particularly preferred transport salts include LiFSI or NaFSI. In some embodiments, when the electrode is a graphite anode, the electrode composition comprises graphite; optionally at least one conductivity enhancing additive; optionally at least one non-ionically conductive polymeric binder; at least one OIPC; and at least one transporting ion salt.

[0083] More preferably, the graphite anode composition contained the following components in the recited amounts: about 40 wt % to about 96 wt % graphite; optionally, up to about 10 wt % of at least one conductivity enhancing additive; optionally, up to about 10 wt % of at least one polymeric binder; about 3 wt % to about 50 wt % of at least one OIPC; and about 0.5 wt % to about 5 wt % of at least one ion transport salt.

[0084] In one embodiment, a preferred graphite anode composition includes about 40 wt% to about 96 wt% graphite; optionally, up to 0 wt% to about 5 wt% carbon black; optionally, up to 0 wt% to about 5 wt% Na-CMC; about 3 wt% to about 50 wt% [Cmpyr][FSI]; and about 0.75 wt% to about 3.75 wt% LiFSI.

[0085] It is understood that the preferred composite contains as much electroactive material as possible to ensure high charge and discharge capacity. In one embodiment, a preferred graphite anode composition includes about 35 wt% graphite; about 5 wt% carbon black; about 5 wt% Na-CMC; about 50 wt% [Cmpyr][FSI]; and about 3.75 wt% LiFSI.

[0086] In some embodiments, when the electrode is a conversion reaction active material cathode, the electrode composition comprises a reversible redox couple material derived from a transition metal salt, at least one conductivity enhancing additive, at least one OIPC, and at least one ion transport salt.

[0087] In some embodiments, when the electrode is a conversion reaction active material electrode cathode, the electrode composition comprises about 40 wt % to about 95 wt % of a reversible redox couple material derived from a transition metal salt, about 2 wt % to about 20 wt % of graphene, about 1 wt % to about 50 wt % of an OIPC, and about 0.75 wt % to about 3.75 wt % of a transport ion salt.

[0088] Particularly preferred devices have about 90 to about 95 wt % graphite. In some embodiments, the amount of transport ions may be much higher. For example, up to 50 mol% of ion transport salt (e.g., Li or Na salt) to OIPC can be used in the composite, i.e., up to about 1:1 molar ratio of ion transport salt (e.g., Li or Na salt) to OIPC is preferably used. Such levels are preferred to improve conductivity and stability.

[0089] Preferred transition metal salts may be selected from the group consisting of iron borates, such as Fe(BF4)2 salts, preferably Fe(BF4)2·6H2O; copper fluorides, preferably CuF2; cobalt fluorides, preferably CoF3; cobalt chlorides, preferably CoCl2·6H2O; iron chlorides, preferably FeCl3. Preferably, the transition metal salt is Fe(BF4)2·6H2O, Co(II)TFSI, Fe(II) triflate or Ni(PO3)2. In a preferred embodiment, the transition metal salt is Fe(BF4)2·6H2O. Advantageously, one or more new material phases are formed in the composition, as for example in the case of Fe(BF4)2·6H2O, Co(II)TFSI, Fe(II) triflate or Ni(PO3)2, especially in combination with the OIPC or OIPC complex described herein. A preferred composition comprises about a 1:1 mol% combination of OIPC and an inorganic metal salt to form an OIPC-metal salt complex. Preferably, the OIPC / transport ion salt complex is selected from the group consisting of CMpyrBF4 and LiFSI; CMpyrFSI and LiFSI; or CMpyrTFSI and LiFSI. In a preferred embodiment, the electrode composition comprises 76 wt% Fe(BF4)2·6H2O; 10 wt% graphene; and 14 wt% 1:1 CMpyrBF4:14 wt% LiFSI.

[0090] Ion transporting interlayers, e.g., solid electrolytes - Suitable ion transporting interlayers may comprise any solid polymer, glass or ceramic having suitable ionic conductivity, e.g., OIPC, IL, ion transporting salt, or composite of such materials with both. Suitable interlayers comprising a solid electrolyte for use in preferred ASS devices include any solvent-free inorganic solid electrolyte (ISE), solid polymer electrolyte (SPE), and composite polymer electrolyte (CPE). Inorganic solid electrolytes (ISE) can be any of a variety of ceramics, e.g., oxides (e.g., Li 1.3 Al 0.3 Ti 1.7(PO4)3(LATP), SiO2, Al2O3, TiO2, LiAlO2), sulfides (e.g., Li2S·P2S5, (LPS)) and phosphate-based inorganic materials, LISICON, garnets (e.g., Li5La3M2O 12 ), NASICON, lithium nitride, lithium hydride, perovskite materials, and glass-ceramics that assume an amorphous state instead of an ordered crystalline structure. Organic solid electrolytes are preferred for their compatibility with existing battery manufacturing lines.

[0091] Suitable solid polymer electrolytes include any solvent-free salt solution in a polymer host material that conducts ions through the polymer chain. Typical solid polymer electrolytes include polyethylene oxide (PEO), polyvinylidene fluoride (PVdF), polycarbonate, polyester, polynitrile, polyalcohol, polyamine, polysiloxane, and fluoropolymer. In some embodiments, ionogels are preferably used as solid electrolytes. Ionogels are composite materials that include ionic liquids or OIPCs immobilized by inorganic or polymeric matrices that include the above materials. Preferably, the solid polymer is doped with ionic liquids and / or OIPCs. In particular, polymerized ionic liquids, i.e., poly(ionic liquids) (polyILs), represent a promising class of polymer hosts that exhibit high dielectric constants and high chemical / electrochemical stability. Desirably, the electrolyte is a poly-IL or an ionic and non-ionic block copolymer, such as poly(styrene-b-1-((2-acryloyloxy)ethyl)-3-butylimidazolium bis(trifluoromethanesulfonyl)imide, a so-called PILBLOC polymer incorporating an ionic liquid and a transport ion salt, such as C2mpyrFSI and LiFSI. Exemplary polymers are described in US2020 / 0280095. In other studies, a poly-IL, poly(diallyldimethylammonium) bis(trifluoromethanesulfonyl)imide (PDADMANTf2), was shown to promote dissociation of Li salts and transport Li +It has been shown that this can improve transport. Preferably, the electrolyte comprises a mixed ionic liquid, such as poly(diallyldimethylammonium) bis(trifluoromethanesulfonyl)imide (PDADMANTf2), and a transport ion salt.

[0092] Desirably, the ion transport interlayer, e.g., any solid electrolyte comprising a gelling polymer, ceramic or glass, may be provided as a composite comprising an OIPC or OIPC composite, preferably the same as that used in the electrodes described elsewhere herein. In some embodiments, the interlayer is provided as a membrane. In some embodiments, the interlayer comprises a fluoropolymer such as polyvinylidene fluoride (PVdF) or a polymer such as polypropylene. Desirably, the interlayer comprises an ionically conductive but electronically insulating material, including at least one transport ion salt, e.g., one or more of a Na or Li salt; and an organic ionic liquid polymer (OIPC), ideally the same as that used in the electrodes.

[0093] In one example, the interlayer is a solid electrolyte comprising a fluoropolymer such as PVdF. Preferably, the PVdF is in the form of fibers, suitable nanofibers, especially PVdF membranes coated with OIPC, such as [C2mpyr][FSI], or a complex of OIPC and a transport ion salt, such as Na or Li ion salts used in energy storage applications. When a composite is used as a coating for the membrane, preferably the composite comprises [C2mpyr][FSI] and LiFSI, preferably about 40 wt% [C2mpyr][FSI]:LiFSI. About means ±5%. One preferred ion transport interlayer / electrolyte that can be used is a mechanically reinforced composite polymer electrolyte comprising electrospun nano poly(vinylidene fluoride) (PVDF) fibers treated with a high ratio of ionic liquid and / or OIPC and a transport ion salt (e.g. LiFSI) to achieve high ionic conductivity.

[0094] In one embodiment, a complex of [C3mpyr][FSI] and 3.2mLiFSI was mixed with PDADMANTf2 (60 wt%:40 wt%) by adding a suitable solvent such as acetonitrile and stirred at room temperature until a homogenous solution was obtained. The solution was then cast onto a PVDF fibrous matrix to form the composite polymer electrolyte exemplified herein.

[0095] Energy storage device - One aspect of the present invention provides an energy storage device as described herein. A preferred device includes one or more electrodes as described herein, including an OIPC or OIPC complex ion binder, a counter electrode, and an ion transporting intermediate layer (e.g., a solid electrolyte), preferably a solid electrolyte such as a solid polymer composite (e.g., microporous polypropylene or PVdF nanofibers) having an OIPC complex associated therewith. Desirably, the energy storage device is configured as an all-solid-state battery. A preferred all-solid-state battery is configured as a lithium or sodium all-solid-state battery. In some preferred embodiments, the device may include an OIPC anode as described herein or an OIPC cathode as described herein. In such cases, the non-OIPC electrode may be any other conventionally used electrode. In some cases, the device may include an OIPC anode as described herein and an OIPC cathode as described herein.

[0096] Preferably, the electrolyte of the energy storage device is a solid electrolyte, in particular a solid polymer electrolyte comprising OIPC. In one embodiment, the polymer electrolyte comprises PVdF coated with OIPC / transport ion salt complex. The PVdF is preferably electrospun PVdF in the form of a membrane. Suitably, the polymer electrolyte comprises poly(diallyldimethylammonium). Preferably, the polymer electrolyte comprises poly(diallyldimethylammonium) bis(trifluoromethanesulfonyl)imide (PDADMA.NTf2).

[0097] In one embodiment, the energy storage device has a solid polymer electrolyte comprising C3mpyrFSI and LiFSI, preferably mixed with PDADMA.NTf2. Desirably, the polymer electrolyte is C3mpyrFSI comprising 3.2mLiFSI mixed with PDADMA.NTf2 in a ratio of 60 wt%:40 wt%. Desirably, the polymer electrolyte is C3mpyrFSI comprising 3.2mLiFSI mixed with PDADMA.NTf2 in a ratio of 60 wt%:40 wt%.

[0098] In one embodiment, the energy storage device has a polymer electrolyte type interlayer comprising an ionic liquid, preferably C3mpyrFSI and LiFSI, mixed with poly(styrene-b-1-((2-acryloyloxy)ethyl)-3-butylimidazolium bis(trifluoromethanesulfonyl)imide) (EMIM TFSI).

[0099] Triblock ionogel polymers suitable for use are described in U.S. Patent Application Serial No. 16 / 649,753,2020, and Journal of The Electrochemical Society 167(7), 070525, the contents of which are incorporated herein by reference.

[0100] The present invention extends to the use of an organic ionic plastic crystal (OIPC) as an internal ionic binder in a conversion material electrode. Preferably, the conversion material is for a cathode. Alternatively, the conversion material is for an anode.

[0101] Definitions - As used herein, the expressions "energy storage device" or "electrochemical cell" are intended to mean a cell that converts chemical energy to electrical energy or electrical energy to chemical energy based on specific interactions between transported metal ions and a negative electrode. Examples of such interactions include chemical oxidation / reduction, intercalation / insertion, and alloying / dealloying. As understood in the art, such specific interactions also include the collective migration of electrons within the negative electrode, thereby generating an electric current in an external electrical circuit connected to the negative electrode.

[0102] In the context of the present invention, the expression "alloying / dealloying" as used herein denotes a mechanism that provides a reversible and intimate incorporation of transport metal ions within the atomic structure of the electrode. The principles and requirements of alloying or so-called reconstituted reaction electrodes are well established [Huggins][Guo], and these include various Li-Al, Li-Si, Li-Sb, Li-Bi, Li-Sn, Li-Pb, Li-In, Li-Ga and Li-Cd binary systems, as well as ternary systems and above. Similarly, sodium and other target ions (Mg, Ca, K...) have also been demonstrated, and their phase reactions and material engineering have been widely reported [Dahbi][Farbod][Orzech][Zhang][Cheng][Baltruschat]. In general, the various material engineering and design approaches applicable to each target ion and alloying system designed to improve the utilization, efficiency and stability of alloying / dealloying reactions have been shown to be applicable across multiple systems [Guo][Liang]. Huggins, Robert A. “Materials science principles related to alloys of potential use in rechargeable lithium cells.” Journal of Power Sources 26.1-2(1989):109-120. Dahbi, Mouad et al., “Negative electrodes for Na-ion batteries.” Physical chemistry chemical physics 16.29(2014):15007-15028.Farbod, Behdokht et al., “Anodes for sodium ion batteries based on tin-germanium-antimony alloys.” ACS nano 8.5(2014):4415-4429.Orzech, Marcin W. et al., “Synergic effect of Bi,Sb and Te for the increased stability of bulk alloying anodes for sodium-ion batteries.” Journal of Materials Chemistry A 5.44(2017):23198-23208.Wang,Anniら、“Bi-based electrode materials for alkali metal-ion batteries.” Small 16.48(2020):2004022.Zhang,Huang,Ivana Hasa, and Stefano Passerini.“Beyond Insertion for Na-Ion Batteries:Nanostructured Alloying and Conversion Anode Materials.” Advanced Energy Materials 8.17(2018):1702582.Cheng,Yingwenら、“Interface promoted reversible Mg insertion in nanostructured Tin-Antimony Alloys.” Advanced Materials 27.42(2015):6598-6605.Baltruschat,Helmut, and Da Xing.“Investigation of Calcium Alloying with Sb,Sn and Bi As Negative Electrode Materials for Rechargeable Calcium Battery in Non-Aqueous Electrolytes.” ECS Meeting Abstracts.No.6.IOP Publishing,2021.Guo,Songtaoら、“Architectural Engineering Achieves High-Performance Alloying Anodes for Lithium and Sodium Ion Batteries.” Small 17.19(2021):2005248.Liang,Suzheら、“A chronicle review of nonsilicon (Sn,Sb,Ge)-based lithium / sodium-ion battery alloying anodes.” Small Methods 4.8(2020):2000218, the contents of which are incorporated herein by reference.

[0103] As used herein, a "negative electrode" refers to an electrode from which electrons leave a cell during discharge as a result of interactions between the electrode and transport ions of the type described herein. With reference to its function during discharge, the negative electrode is also commonly referred to in the art as an "anode." The negative electrode may include (or be made from) a material that can reversibly intercalate transport ions within its atomic structure, interact with (e.g., absorb / desorb) the transport ions by promoting reversible oxidation / reduction reactions, or promote alloying / dealloying reactions with the transport ions.

[0104] As used herein and as will be appreciated by those skilled in the art, the expression "positive electrode" refers to the electrode through which electrons enter the cell during discharge. With reference to its function during discharge, the positive electrode is also commonly referred to as the "cathode." The positive electrode may include (or be made from) a material that can reversibly intercalate transport ions within its lattice structure, absorb / desorb transport ions by reversible oxidation / reduction reactions, or promote alloying / dealloying reactions with the transport ions described herein.

[0105] The term "alkyl" as used herein describes a group composed of at least one carbon and hydrogen atom and includes linear, branched or cyclic alkyl, e.g., C 1~20 Alkyl, e.g. C 1~10 or C 1~6Examples of linear and branched alkyls include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, t-butyl, n-pentyl, 1,2-dimethylpropyl, 1,1-dimethylpropyl, hexyl, 4-methylpentyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl, 3,3-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, and 1,2,2-trimethylpropyl. , 1,1,2-trimethylpropyl, heptyl, 5-methylhexyl, 1-methylhexyl, 2,2-dimethylpentyl, 3,3-dimethylpentyl, 4,4-dimethylpentyl, 1,2-dimethylpentyl, 1,3-dimethylpentyl, 1,4-dimethylpentyl, 1,2,3-trimethylbutyl, 1,1,2-trimethylbutyl, 1,1,3-trimethylbutyl, octyl, 6-methylheptyl, 1-methylheptyl, 1,1,3,3-tetramethylbutyl, nonyl, 1- , 2-, 3-, 4-, 5-, 6- or 7-methyloctyl, 1-, 2-, 3-, 4- or 5-ethylheptyl, 1-, 2- or 3-propylhexyl, decyl, 1-, 2-, 3-, 4-, 5-, 6-, 7- and 8-methylnonyl, 1-, 2-, 3-, 4-, 5- or 6-ethyloctyl, 1-, 2-, 3- or 4-propylheptyl, undecyl, 1-, 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-methyldecyl, 1-, 2-, 3-, 4-, 5-, 6 Examples of cyclic alkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohex ...When an alkyl group is generally referred to as "propyl," "butyl," etc., it is understood that this can refer to any of the straight-chain, branched, and cyclic isomers, where appropriate. Alkyl groups may be optionally substituted with one or more substituents, as defined herein, including substituents in which a carbon is replaced with a heteroatom (O, N, S, etc.).

[0106] Examples of optional substituents include alkyl (e.g., C 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 1~6 alkyl), hydroxyalkyl (e.g., hydroxymethyl, hydroxyethyl, hydroxypropyl), alkoxyalkyl (e.g., methoxymethyl, methoxyethyl, methoxypropyl, ethoxymethyl, ethoxyethyl, ethoxypropyl, etc.), alkoxy (e.g., methoxy, ethoxy, propoxy, butoxy, cyclopropoxy, cyclobutoxy, etc.) 1~6 alkoxy), halo, trifluoromethyl, trichloromethyl, tribromomethyl, hydroxy, phenyl (which itself can be, for example, C 1~6 Alkyl, halo, hydroxy, hydroxyC 1~6 Alkyl, C 1~6 Alkoxy, HaloC 1~6 Alkyl, cyano, nitroOC(O)C 1~6 alkyl, and amino), benzyl (which itself can be, for example, 1~6 Alkyl, halo, hydroxy, hydroxyC 1~6 Alkyl, C 1~6 Alkoxy, HaloC 1~6 Alkyl, cyano, nitroOC(O)C 1~6 alkyl, and amino), phenoxy (phenyl itself can be, for example, C 1~6 Alkyl, halo, hydroxy, hydroxyC 1~6 Alkyl, C 1~6 Alkoxy, HaloC 1~6 Alkyl, cyano, nitroOC(O)C 1~6benzyloxy (which itself may be further substituted by, for example, C 1~6 Alkyl, halo, hydroxy, hydroxyC 1~6 Alkyl, C 1~6 Alkoxy, HaloC 1~6 Alkyl, cyano, nitroOC(O)C 1~6 alkyl, and amino), amino, alkylamino (e.g., C 1~6 Alkyl, for example, methylamino, ethylamino, propylamino, etc.), dialkylamino (for example, C 1~6 Alkyl, e.g., dimethylamino, diethylamino, dipropylamino), acylamino, e.g., NHC(O)CH3, phenylamino (phenyl itself, e.g., C 1~6 Alkyl, halo, hydroxy, hydroxyC 1~6 Alkyl, C 1~6 Alkoxy, HaloC 1~6 Alkyl, cyano, nitroOC(O)C 1~6 alkyl, and amino), nitro, formyl, -C(O)-alkyl (e.g., C 1~6 alkyl, e.g. acetyl), OC(O)-alkyl (e.g. C 1~6 alkyl, e.g. acetyloxy), benzoyl (the phenyl group itself is e.g. C 1~6 Alkyl, halo, hydroxyhydroxyC 1~6 Alkyl, C 1~6 Alkoxy, HaloC 1~6 Alkyl, cyano, nitroOC(O)C 1~6 C=O, CO2H, substitution of CH2 by CO2 alkyl (e.g., C=O, CO2H, CO2 alkyl, such as methyl ester, ethyl ester, propyl ester, butyl ester, etc.), 1~6 alkyl), CO2phenyl (phenyl itself is e.g. C 1~6 Alkyl, halo, hydroxy, hydroxylC 1~6 Alkyl, C 1~6 Alkoxy, HaloC 1~6 Alkyl, cyano, nitroOC(O)C 1~6alkyl, and amino), CONH, CONHphenyl (phenyl itself can be, for example, C 1~6 Alkyl, halo, hydroxy, hydroxylC 1~6 Alkyl, C 1~6 Alkoxy, HaloC 1~6 Alkyl, cyano, nitroOC(O)C 1~6 alkyl, and amino), CONH benzyl (benzyl itself is, for example, C 1~6 Alkyl, halo, hydroxylC 1~6 Alkyl, C 1~6 Alkoxy, HaloC 1~6 Alkyl, cyano, nitroOC(O)C 1~6 alkyl, and amino), CONH alkyl (e.g., methyl ester, ethyl ester, propyl ester, butyl amide, etc. 1~6 alkyl)CONHdialkyl (e.g., C 1~6 alkyl)aminoalkyl (e.g., HNC 1~6 Alkyl-, C 1~6 AlkylHN-C 1~6 Alkyl- and (C 1~6 Alkyl)2N-C 1~6 alkyl-), thioalkyl (e.g., HSC 1~6 alkyl-), carboxyalkyl (e.g., HO2CC 1~6 alkyl-), carboxy ester alkyl (e.g., C 1~6 Alkyl O2CC 1~6 alkyl-), amidoalkyl (e.g., HN(O)CC 1~6 Alkyl-, H(C 1~6 Alkyl)N(O)CC 1~6 alkyl-), formyl alkyl (e.g., OHCC 1~6 alkyl-), acylalkyl (e.g., C 1~6 Alkyl(O)CC 1~6 alkyl-), nitroalkyl (e.g., ONC 1~6 alkyl-), sulfoxide alkyl (e.g., R f (O)SC 1~6Alkyl, where R f is as defined herein, for example alkyl, e.g. C 1~6 Alkyl(O)SC 1~6 alkyl-), sulfonylalkyl (e.g., Rf(O)SC 1~6 Alkyl, where R f is as defined herein, for example alkyl, e.g. C 1~6 Alkyl(O)2SC 1~6 alkyl-), sulfonamidoalkyl (e.g., 2HR f N(O)SC 1~6 Alkyl, where R f is as defined herein, for example alkyl, e.g. H(C 1~6 Alkyl)N(O)SC 1~6 alkyl-.

[0107] The term "halogen" ("halo") refers to fluorine, chlorine, bromine or iodine (fluoro, chloro, bromo or iodo). Preferred halogens are chlorine, bromine or iodine.

[0108] Heterocyclyl groups may be saturated or partially unsaturated, i.e. may have one or more double bonds. Particularly preferred heterocyclyls are 5-6 and 9-10 membered heterocyclyls. Suitable examples of heterocyclyl groups include azuridinyl, oxiranyl, thiiranyl, azetidinyl, oxetanyl, thietanyl, 2H-pyrrolyl, pyrrolidinyl, pyrrolinyl, piperidyl, piperazinyl, morpholinyl, indolinyl, imidazolidinyl, imidazolinyl, pyrazolidinyl, thiomorpholinyl, dioxanyl, tetrahydrofuranyl, tetrahydropyranyl, tetrahydropyrrolyl, tetrahydrothiophenyl, pyrazolinyl, dioxan ... Examples of heterocyclyl groups include salanyl, thiazolidinyl, isoxazolidinyl, dihydropyranyl, oxazinyl, thiazinyl, thiomorpholinyl, oxathiyl, dithianyl, trioxanyl, thiadiazinyl, dithiazinyl, trithianyl, azepinyl, oxepinyl, thiepinyl, indenyl, indanyl, 3H-indolyl, isoindolinyl, 4H-quinolazinyl, chromenyl, chromanyl, isochromanyl, pyranyl and dihydropyranyl. Heterocyclyl groups may be optionally substituted with one or more optional substituents as defined herein. The term "heterocyclylene" is intended to indicate the divalent form of heterocyclyl.

[0109] The term "heteroaryl" includes any monocyclic, polycyclic, fused or conjugated hydrocarbon residue, in which one or more carbon atoms are replaced by heteroatoms to provide an aromatic residue. Preferred heteroaryls have 3-20, for example 3-10, ring atoms. Particularly preferred heteroaryls are 5-6 and 9-10 membered bicyclic ring systems. Suitable heteroatoms include O, N, S, P and Se, especially O, N and S. When two or more carbon atoms are replaced, this may be by two or more of the same or different heteroatoms. Suitable examples of heteroaryl groups include pyridyl, pyrrolyl, thienyl, imidazolyl, furanyl, benzothienyl, isobenzothienyl, benzofuranyl, isobenzofuranyl, indolyl, isoindolyl, pyrazolyl, pyrazinyl, pyrimidinyl, pyridazinyl, indolizinyl, quinolyl, isoquinolyl, phthalazinyl, 1,5-naphthyridinyl, quinozalinyl, quinazolinyl, quinolinyl, oxazolyl, thiazolyl, isothiazolyl, isoxazolyl, triazolyl, oxadialzolyl, oxatriazolyl, triazinyl, and furazanyl.Heteroaryl groups may be optionally substituted by one or more optional substituents as defined herein.The term "heteroarylene" is intended to indicate a divalent form of heteroaryl.

[0110] The term "sulfoxide", either alone or in combination, refers to the group R f -S(O)R f wherein R is selected from hydrogen, alkyl, alkenyl, alkynyl, aryl, heteroaryl, heterocyclyl, carbocyclyl, and aralkyl. f An example of this is C. 1~20 Alkyl, preferably C 1~6 Alkyl, most preferably C 1~3 Alkyl, phenyl and benzyl are included.

[0111] The term "sulfonyl", either alone or in compound, refers to the group S(O)-R fR f is selected from hydrogen, halide, alkyl, alkenyl, alkynyl, aryl, heteroaryl, heterocyclyl, carbocyclyl and aralkyl. Preferred examples of Rf include 1~20 Alkyl, phenyl and benzyl are included.

[0112] The term "sulfonamide", either alone or in combination, refers to the group S(O)NR f R f wherein each R is independently selected from hydrogen, alkyl, alkenyl, alkynyl, aryl, heteroaryl, heterocyclyl, carbocyclyl, and aralkyl. f An example of this is C. 1~20 alkyl, phenyl and benzyl. In a preferred embodiment, at least one R f is hydrogen. In another embodiment, both R f is hydrogen.

[0113] The term "heteroatom" or "hetero" as used herein in its broadest sense refers to any atom other than carbon atom that may be a member of a cyclic organic group. Specific examples of heteroatoms include nitrogen, oxygen, sulfur, phosphorus, boron, silicon, selenium and tellurium, more particularly nitrogen, oxygen and sulfur.

[0114] As used herein, "about" means ±5% of the stated value. The invention will now be described with reference to the following examples, which should be understood as being illustrative and not limiting of the invention described herein.

[0115] Example 1 OIPC binders in graphite anodes In this first example, the inclusion of an OIPC binder in the form of an OIPC / Li salt complex binder improved the charge rate capability and cyclability of a graphite anode in an all-solid-state battery. An exemplary OIPC, N-ethyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide ([Cmpyr][FSI]), was incorporated as an OIPC / Li salt complex as an ionic binder within the graphite anode at a range of tested OIPC / Li salt binder concentrations. The Li salt used was LiFSI, although other salts could have been used if desired.

[0116] The positive effect of the preferred OIPC binder on charge / discharge rate capability and cycle life has been demonstrated in solid-state cells containing the OIPC / graphite composite anode. In particular, the cell performance of the solid-state cells containing the OIPC / graphite composite anode of the present invention was compared to cells containing a graphite anode with liquid electrolyte (no OIPC). The highest charge capacity ratio was measured for the graphite / OIPC composite anode with 50 wt% OIPC composite ratio (89.5%, 295.7 mAh / g at 2C charge), which was almost the same charge capacity ratio as that of the graphite anode using liquid electrolyte, i.e., not in solid-state cell format (85.7%, 295.9 mAh / g at 2C charge). In the systems tested herein, it was found that a more favorable lithium ion conduction pathway was resolved for the preferred anode with a higher amount of OIPC or an amount of OIPC / Li salt composite up to 50 wt% of the total electrode material. In some embodiments, the transport ion salt is not included directly in the electrode, but the cell can be designed with excess alkali (lithium) ions, for example in the electrolyte or counter electrode, so that lithium is incorporated into the electrode in the desired amount upon cycling. However, for the particular graphite electrode composition studied herein, excess amounts of OIPC composite binder (50 wt%+) caused variability in long-term cyclability. In fact, the most stable discharge capacity retention was obtained using a graphite composite anode with 30 wt% OIPC composite (102.7%, 257.4 mAh / g at 100 cycles). Furthermore, the lithiation / delithiation process of the preferred solid graphite-[C2mpyr][FSI] composite anode of the present invention was evaluated to be stable and reversible.

[0117] A simple electrode fabrication process was utilized that differs from conventional methods in that OIPC composite solution was added to the aqueous graphite anode slurry, ensuring the high applicability of this method to roll-to-roll processes. Another preparation method is shown in Figure X. The surface and cross-sectional structures of the solid graphite composite anodes containing various amounts of OIPC were examined by scanning electron microscope (SEM). Then, the effects of OIPC on the charge rate capability and cyclability of the anodes in the coin cell cycling test were investigated.

[0118] Preparation of solid graphite electrodes - An exemplary OIPC, N-ethyl-N-propylpyrrolidinium bis(fluorosulfonyl)imide ([C2mpyr][FSI], Boron Molecular, >99%), was used after drying under vacuum at 60 °C for >12 h. Lithium bis(fluorosulfonyl)imide (LiFSI, Nippon Shokubai, LF-101) was used as received. Both [C2mpyr][FSI] and LiFSI were weighed into an Ar atmosphere glove box (O2<10.0 ppm, H2O<0.1 ppm), and then acetone (Chem-Supply, >99.5%) was added outside the glove box to make a 40 wt% [C2mpyr][FSI] complex acetone solution (90 mol% [C2mpyr][FSI] and 10 mol% LiFSI). 1.2 g of sodium carboxymethylcellulose (Na-CMC, Sigma-Aldrich, average molecular weight: 70,000 g / mol) was dissolved in 78.6 g of distilled water at room temperature using a magnetic stirrer. After ensuring that Na-CMC was completely dissolved in water, 1.2 g of carbon black (C65, Imerys Graphite&Carbon) was added to the solution, which was then stirred at room temperature for >12 hours to obtain a dispersion of 1.5 wt% Na-CMC+1.5 wt% C65 in water. For electrode slurry preparation, graphite (Merck, ultra-pure fine powder) was weighed into a separate vial. The desired amount of 40 wt% [C2mpyr][FSI] complex acetone solution was dropped into this vial, followed by the addition of an appropriate amount of Na-CMC+C65 dispersion. This graphite slurry was stirred at room temperature for >12 hours to obtain a homogenous mixture. The slurry was then coated onto a Cu sheet (thickness: 20 μm) using a doctor blade with a wet gap of 80 μm. The solvent in the coated slurry was evaporated in an oven at 80 °C for >1 h. The dried sheets were punched out to obtain solid graphite electrode disks with a diameter of 8 mm. Each disk was sandwiched between two Teflon disks (φ16 mm) and then pressed using a pellet die (φ16 mm) under 3,000 psi at room temperature. After pressing, the weight and thickness of the electrode disks were measured. The electrode disks were further vacuum dried at 60 °C for >12 h and used for the assembly of coin cells.

[0119] The composition of the graphite anode without OIPC composite ([C2mpyr][FSI]+LiFSI) was 90 wt% graphite, 5 wt% C65, and 5 wt% Na-CMC. The ratio of graphite anode to [C2mpyr][FSI] composite was set to be (100-x):x wt% (x=0, 15, 30, or 50). The actual composition, electrode loading, and density of the solid graphite anode disks tested are summarized in Table 1 below.

[0120] [Table 1]

[0121] Preparation of Interlayer for Graphite Electrode Coin Cell Test - Electrospun poly(vinylidene fluoride) (PVdF) fibers were fabricated by a procedure previously described (ChemSusChem 10, No.15(2017):3135-3145). PVdF fibers were provided on an Al sheet and punched into φ12.7 mm disks. The above-mentioned 40 wt% [C2mpyr][FSI] complex acetone solution was dropped onto the PVdF fiber disks, which were then dried at room temperature for >3 h under Ar atmosphere. The coated PVdF fiber disks (coated with the dried [C2mpyr][FSI] complex) were then further vacuum dried at 60 °C for >12 h. Each disk was sandwiched between two Teflon disks (φ16 mm) and pressed under Ar atmosphere using a pellet die (φ16 mm) at room temperature under a pressure of 2,000 psi. After removing the Al sheet, the resulting PVdF-[C2mpyr][FSI] composite fiber disk was used as the solid electrolyte and separator in a coin cell assembly. The composition of the disk was 90 wt% [C2mpyr][FSI] composite and 10 wt% PVdF.

[0122] Coin cell assembly - CR2032 type coin cells were assembled in an Ar-filled glove box. Lithium strips (Sigma-Aldrich, thickness: 0.3 mm) were brushed on both sides and punched into round disks (φ10 mm). The brushed lithium disks were attached to the coin cell components and covered with a PVdF-[C2mpyr][FSI] composite fiber disk. The solid graphite electrode under study was then placed on top. After crimping, the coin cells were transferred to a 50°C oven and stored for >12 hours to ensure temperature equilibration of the battery testing environment. The coin cells were used to study lithium metal plating and stripping from the graphite anode.

[0123] Battery Testing - All battery tests were performed at 50°C using either a Neware battery cycler or a BioLogic VMP-300 potentiostat. The 1C current rate (mA) was calculated as follows: multiply the active material weight (g) of each cell by the actual discharge capacity of the graphite used in this study (340mAh / g) and divide this number by 1 hour.

[0124] First, the coin cells were cycled three times using constant current-constant voltage (CCCV) mode with a current rate of 0.1C for charging (lithiation) and constant current (CC) mode with a current rate of 0.1C for discharging (delithiation). The lower and upper cutoff voltages were 0.005V and 1.5V, respectively. The cutoff current rate for CV charging was 0.05C, and the rest time between charging and discharging was 10 minutes. After three cycles, a charge rate test was performed at 50°C. Specifically, the test conditions were the same as those for the first three cycles except for the test mode and the current rate during each charge. The CC mode was used, and the charge current rate was changed for each cycle in the following order: 0.1C → 0.2C → 0.5C → 1C → 2C → 0.1C (total of 6 cycles). The charge rate capability was evaluated as the ratio of the charge capacity at higher C rates (>0.1C) to the capacity measured in the first 0.1C-CC charge.

[0125] After the charge rate test, selected cells were further cycled at 50°C. To confirm the capacity, the cells were first cycled at 0.1C-CC. Then, the cells were tested at 0.2C-CC charge and 0.1C-CC discharge for 99 cycles. Finally, the capacity after cycling test was measured at 0.1C-CC. The cut-off voltage and rest time were the same as those of the first three cycles.

[0126] Structural Analysis - SEM of selected solid graphite anodes was carried out using a JSM IT300 series microscope. A razor blade was used to obtain cross sections of the electrodes. Specifically, the electrode was sandwiched between two pieces of plastic film and fixed in a holder. A section was then made from the electrode surface to the copper current collector while maintaining a point contact between the electrode and the fresh cutting edge of the razor blade. All samples were prepared in a glove box and transferred to the SEM observation chamber using an air sensitive holder. Elemental analysis of the electrodes was performed using an Oxford X-Max50mm 2 This was done by EDX using an EDX detector.

[0127] Results and Discussion - Example 1 - OIPC binder in graphite anode - The initial charge-discharge behavior of the solid graphite-[C2mpyr][FSI] composite anode was compared with that of the equivalent graphite anode using liquid electrolyte (1.0M LiPF6 in EC-DEC-DMC). Figure 1a shows the charge-discharge of the solid graphite-[C2mpyr][FSI] composite anode with 30 wt% OIPC content. For reference, the charge-discharge profile of the graphite anode using liquid electrolyte is also shown in Figure 1b. At the first charge, a peak appeared at about 0.4 V for the solid graphite-[C2mpyr][FSI] composite anode, which was also found for other electrode compositions (i.e., OIPC contents of 0 wt%, 15 wt% and 50 wt%, see Figure 2 for their charge-discharge profiles). This is due to (i) the formation of a solid electrolyte interphase (SEI) influenced by the decomposition of [C2mpyr][FSI], (ii) the formation of [C2mpyr] + This can be attributed to one of two causes of the intercalation of [FSI] into graphite in the liquid electrolyte. -The graphite / Li half-cell containing an anion exhibits a large irreversible capacity upon first charge and a shoulder in the charge profile between 0.2 and 1.5 V. In contrast, [C3mpyr] + and Li + Cationic bis(trifluoromethylsulfonyl)imide (TFSI) - The graphite anode in the ionic liquid (C3mpyr) at 0.4-0.7 V + It has been reported to exhibit reversible intercalation of cations.

[0128] The characteristic peak was observed only in the first charging step, and the charge-discharge profiles of the subsequent cycles were almost identical to those of the graphite anode with liquid electrolyte (Figure 1a vs. Figure 1b, 2nd and 3rd cycles). Therefore, the origin of the peak is attributed to the SEI formation derived from the decomposition of OIPC. Table 2 summarizes the capacity and coulombic efficiency of the solid graphite-[C2mpyr][FSI] composite anode and the graphite anode with liquid electrolyte.

[0129] [Table 2]

[0130] The graphite / Li half-cell with liquid electrolyte shows a first cycle Coulombic efficiency of 84.5%, while the half-cell with solid graphite-[C2mpyr][FSI] composite anode shows much lower first cycle Coulombic efficiency (34.9–56.5%). This is due to the irreversible capacity caused by the SEI formation mentioned above. For all half-cells, the Coulombic efficiency increases gradually with cycle number. The detailed dependence of the Coulombic efficiency and discharge capacity on the OIPC composite ratio is discussed below. In brief, higher OIPC composite ratios (>30 wt%) showed higher third cycle Coulombic efficiency and discharge capacity, which were close to those measured for the graphite anode with liquid electrolyte. This suggests that a higher OIPC composite content (>30 wt%) results in better ionic conduction in the anode compared to lower amounts of OIPC. Surprisingly, the solid graphite anode without OIPC composite was also cycleable due to the interparticle diffusion of lithium ions. The increase in capacity and efficiency is not fully evident after three cycles, and the improvement in stability and rate performance due to the incorporation of OIPC becomes more evident at longer cycling times, as shown later (Figure 5).

[0131] Charge rate performance - Figure 3 shows the charging curves of the solid graphite-[C2mpyr][FSI] composite anode with 30 wt% OIPC at various C-rates. With increasing charge C-rate, the plateaus of the curves became shorter and less pronounced, and the charge capacity decreased at higher C-rates. The same trend was found for other anode compositions, and the degree of decrease in charge capacity with increasing C-rate depended on the anode composition.

[0132] Figure 4a shows the charge capacity ratios at various C-rates for solid graphite-[C2mpyr][FSI] composite anodes with OIPC composite ratios of 0, 30, and 50 wt% versus graphite anodes with liquid electrolyte (see discussion below for charge rate capability of 15 wt% sample). The difference in charge rate capability comes from the difference in the structure inside the anode. The fastest decrease in charge capacity with increasing C-rate was measured for solid graphite anodes without OIPC composite (0 wt%), followed by electrodes with 15 wt%, 30 wt%, and 50 wt% OIPC composites. This can be attributed to three reasons: (i) the smallest (zero) contact area between the bulk OIPC composite and the graphite particles, (ii) the relatively unstable contact between the graphite particles and the copper current collector in the absence of OIPC, and (iii) the loss of good end-to-end contact during charging in the absence of OIPC. The smaller electrolyte / electrode contact area results in the formation of a larger interfacial resistance. Solid graphite anodes have no electrolyte inside (due to the absence of liquid), and therefore SEI formation on the current collector is not possible. In contrast, the SEI on copper in liquid electrolyte systems is organic-rich, improving the adhesion of graphite particles to the current collector. However, the electrode / current collector contact in the solid graphite anode of the present invention relies mainly on the polymer binder (Na-CMC) and van der Waals forces between the graphene layer and the bare current collector substrate, which makes it prone to partial contact loss between the graphite particles and the current collector during charging. The difference in electrode / current collector contact is discussed below. With regard to the orientation dependence of graphite particles, it is known that lithium intercalation into graphite occurs across the edge faces. Since the defect-free basal planes of graphite particles are inert to lithium intercalation, lithium ion conduction between graphite particles in solid graphite anodes without OIPC composites is expected to occur at the contact points between the edge faces. However, as the charging rate increases, so does the intercalation of lithium through each contact point, which can lead to a rapid volume expansion of the graphite particles, causing the contact points to slip slightly and change their orientation from end-to-end contacts to unfavorable base-to-edge or base-to-base contacts.During charging from the delithiated to the lithiated state, a graphite particle expands along its c-axis by 10%, so such contact modifications may not be negligible.

[0133] The decrease in charge capacity with increasing C-rate becomes weaker as the OIPC composite ratio inside the anode of the electrode increases. This is because some or all of the three adverse effects mentioned above are nullified. The increase in the OIPC composite ratio gives the graphite particles a larger electrolyte / electrode contact area, which reduces the interfacial resistance between the electrolyte and the electrode. In addition, the OIPC composite plays the role of a binder / adhesive in the anode, improving and / or maintaining the contact of both the electrolyte / electrode and the electrode / current collector, as well as fixing the orientation of the graphite particles at the contact points. Some OIPC ([FSI] - The OIPC-based composites (e.g., OIPC-based) are sticky, which is advantageous in terms of their binder function. This property is typically exhibited by OIPCs in the solid phase I state at handling temperatures (i.e., room temperature). Indeed, the OIPC composite of 90 mol% [C2mpyr][FSI] and 10 mol% LiFSI used in this example is sticky enough to bind the graphite particles. As the ratio of OIPC composite increases, the charge rate capability increases. Importantly, the capacity ratio of the solid graphite-[C2mpyr][FSI] composite anode with an OIPC composite ratio of 50 wt% (89.5% at 2C charge) is almost the same as that of the graphite anode with liquid electrolyte (85.7% at 2C charge). This suggests that at 50 wt%, the OIPC composite fully fills the voids inside the anode, covers the graphite particles, and provides them with favorable lithium ion conduction paths between the bulk OIPC composite. Furthermore, the solid graphite-[Cmpyr][FSI] composite anode can be used at low volume fractions of electrolyte (i.e., the volume fraction of LiFSI, φ 電解質 ≦1.8%), which is higher than that of a solid graphite anode using a liquid electrolyte (φ 電解質= 5.0%, see Table 3 for details). This is one of the advantages of using the OIPC composite, because the amount of lithium salt required in the OIPC composite to improve the charge rate capability is less than that in the liquid electrolyte (Figure 4b). Possible reasons for this difference are discussed below.

[0134] [Table 3]

[0135] Cycle life – Figure 5a shows the charge-discharge profile of the solid graphite-[C2mpyr][FSI] composite anode with 30 wt% OIPC composite ratio during the cycle test. The charge capacity was stable for all cycles. Meanwhile, the discharge capacity gradually improved with increasing cycle number and stabilized at about the 20th cycle. This can be explained as a preconditioning process. This has been reported not only in lithium / lithium symmetric cells with OIPC composite interlayers but also in half cells composed of LiFePO4(LFP) cathode, OIPC composite interlayer, and lithium metal. The preconditioning process is believed to originate from Joule heating, recrystallization of OIPC followed by the formation of small OIPC grains, and the non-uniform concentration profile of lithium ions at the electrolyte / electrode interface. These provide contact points with the more molten eutectic phase and the disordered phase of the OIPC composite, thus facilitating lithium ion conduction. These effects can be induced by cell cycling and reduce the interfacial resistance. Figure 5d summarizes the discharge capacity retention of solid graphite-[Cmpyr][FSI] composite anodes with OIPC composite ratios of 0 wt%, 30 wt%, and 50 wt% during cycling tests (Figures 5a-c). The capacity, CE, and discharge capacity retention during selected cycles are shown in Table 4.

[0136] [Table 4]

[0137] From the 1st to the 20th cycle, all the cells showed an increase in discharge capacity. After that, each cell showed a different discharge capacity retention plot. The solid graphite anode without OIPC composite showed a steady decrease in discharge capacity retention. Its average degradation rate was evaluated to be 0.081% per cycle, and the discharge capacity retention after 100 cycles reached 95.7% (275.3mAh / g). The discharge capacity retention of the solid graphite-[C2mpyr][FSI] composite anode with 30wt% OIPC composite ratio was stable during the cycling test (102.7%, 257.4mAh / g at the 100th cycle). To the best of our knowledge, such ultrastable discharge capacity retention of a solid-state half-cell with an OIPC composite interlayer has only been reported at 80 °C in a cell containing an LFP cathode, an OIPC composite electrolyte of 90 mol% N-ethyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([C2mpyr][TFSI]) and 10 mol% LiTFSI, and lithium metal. Meanwhile, further increasing the OIPC composite ratio up to 50 wt% induced fluctuations in the increase in discharge capacity retention due to unwanted side reactions. A similar trend was found for the Coulombic efficiency (Figure 5e). The Coulombic efficiency also increased from the 1st to the 20th cycle. However, the Coulombic efficiency still showed a gradual rise after the 20th cycle. For example, the coulombic efficiency of the solid graphite-[C2mpyr][FSI] composite anode with 30 wt% OIPC composite ratio rapidly increased from 95.0% at the 2nd cycle to 97.4% at the 20th cycle, and further improved to 98.3% at the 100th cycle. Meanwhile, the coulombic efficiency of the solid graphite-[C2mpyr][FSI] composite anode with 50 wt% OIPC composite ratio began to fluctuate from the 31st cycle. The results suggest that 30 wt% is the most balanced condition in terms of charge rate capability and cycle life, and further increasing the OIPC composite ratio in the solid graphite-[C2mpyr][FSI] composite anode (i.e., 50 wt%) would risk the discharge capacity fluctuation caused by side reactions.

[0138] Structural analysis - The surfaces of the solid graphite anode and the solid graphite-[C2mpyr][FSI] composite anode were observed by SEM at 6,000x magnification. All surfaces show graphite particles partially covered by the foam-like structure of carbon black (Figure 6a-6c). In the solid graphite anode without OIPC composite, clear outlines of each particle were resolved. When more OIPC composite was incorporated into the anode, the outlines of the particles became even more unclear. This suggests that the OIPC composite covers the graphite particles and connects them firmly to each other. Therefore, the more the amount of OIPC composite inside the anode, the smaller the contact resistance between the OIPC composite and the graphite particles can be.

[0139] The results show that the OIPC composite forms a network of lithium ion conductive pathways inside the anode. Although there are some undispersed OIPC composite grains on the surface of the solid graphite-[Cmpyr][FSI] composite anode, the overall anode structure seems homogeneous enough to evaluate the effect of the ratio of incorporated OIPC composites on the half-cell performance. Comparison between SEM images (Figures 6a-6c) suggests that a higher OIPC composite ratio results in a solid graphite anode with better lithium ion conductive pathways. However, since too much OIPC composite (i.e., 50 wt%) leads to unpredictable variations in capacity during cycling tests, the OIPC composite ratio can be fine-tuned based on the gravimetric or volumetric energy density at the desired C-rate and cycling stability (e.g., 30 wt%) to balance them.

[0140] The cross-sections of the solid graphite anode and the solid graphite-[C2mpyr][FSI] composite anode were also resolved to gain further insight into their structural differences. As can be seen from Figure 6d, 6e and Figure 6b, with the increase in the OIPC composite ratio, the contours of the graphite particles become smoother. Also, at higher OIPC composite ratios, more parts of the carbon black are blended with the OIPC composite. These trends are the same as those found in the surface images (Figure 6a-6c). Meanwhile, the cross-sectional images provide information about the arrangement of the graphite particles. It is interesting to note that the graphite particles on the surface are closely packed and face the interlayer at the basal surface, whereas the graphite particles on the interior are randomly oriented with voids, some of which are aligned perpendicular to the copper current collector. This ensures efficient lithium ion insertion / extraction of the solid graphite-[C2mpyr][FSI] composite anode. A random orientation of the inner graphite particles is beneficial because a higher fraction of horizontally oriented graphite particles (i.e., higher anode density) tends to slow down lithium ion conduction.

[0141] Overall, the incorporation of the OIPC composite into the graphite anode not only promotes the lithium ion conduction pathway inside the anode, but also enhances the electrolyte / electrode and electrode / current collector contacts, improving the charge rate capability and cycle life. This opens a new avenue for the development of ASSBs using the OIPC composite as a solid electrolyte incorporated into the electrode. The coulombic efficiency and discharge capacity for the first three cycles of the 15 wt% sample in Table 5 show the capacity and coulombic efficiency of the solid graphite-[C2mpyr][FSI] composite anode with 15 wt% OIPC composite ratio.

[0142] [Table 5]

[0143] Notably, the first coulombic efficiency depends on the OIPC composite ratio inside the graphite anode. As the OIPC composite ratio inside increases from 0 to 30 wt%, the first coulombic efficiency decreases, but further increase in the OIPC composite ratio (up to 50 wt%) improves the first coulombic efficiency. As for the discharge capacity, the graphite anode with liquid electrolyte shows 338.1 mAh / g at the third cycle, whereas a lower third cycle discharge capacity is measured for the solid graphite-[C2mpyr][FSI] composite anode, which also depends on the OIPC composite ratio. The solid graphite-[C2mpyr][FSI] composite anode with 15 wt% OIPC composite shows the lowest third cycle discharge capacity (161.8 mAh / g). Meanwhile, the highest third cycle discharge capacity was found for the anode with 50 wt% OIPC composite (320.5 mAh / g). The dependence on the OIPC composite ratio inside the graphite anode can be explained as follows: First, the addition of a small amount of OIPC composite to the graphite anode leads to the generation of interference layers between the graphite particles. The layers are OIPC composite grains separated from the bulk OIPC composite (in the anode and PVdF fibers), and Li transport from one graphite grain to another graphite grain through the separated OIPC composite grains. + The solid graphite anode without OIPC composite showed higher capacity than the anode with a small amount of OIPC composite (15 wt%), suggesting that the diffusion of Li between the graphite particles + The diffusion of Li through the two interfaces of graphite|[Cmpyr][FSI]+LiFSI (90:10 mol%)|graphite is more favorable than that through the two interfaces. Therefore, the addition of a small amount of OIPC complex may not be favorable for some graphite particles. +Second, the addition of more OIPC composites may connect the separated OIPC composite grains to the bulk grains, thus reducing the amount of deactivated graphite particles. This effect is manifested as an improvement in capacity from 15 wt% to 30 wt% after OIPC composite addition. Third, the improvement in discharge capacity can be improved by further increasing the OIPC composite ratio from 30 wt% to 50 wt%. Most of all graphite particles may be made accessible by the additional amount of OIPC composite in the anode, and the OIPC composite grains may be well connected to each other, providing sufficient Li between the bulk OIPC composite to the graphite particles. + In fact, the anode containing 50 wt% OIPC composite reaches 320.5 mAh / g at the third cycle, which is close to the capacity (338.1 mAh / g) observed for an anode with a proper electrolyte / active material connection using liquid electrolyte. Thus, the large loading of OIPC composite (>30 wt%) in the graphite anode is advantageous in terms of charge / discharge performance for the first three cycles.

[0144] Charge rate capability - Table 6 shows the charge capacity and capacity ratio of the solid graphite-[C2mpyr][FSI] composite anode with 15 wt% OIPC composite ratio at each charge C rate. All the charge capacities were lower than those of other solid graphite-[C2mpyr][FSI] composite anodes and solid graphite anodes without [C2mpyr][FSI] composite at the same charge C rate. As mentioned before, this is attributed to the interfering layer between the graphite particles (i.e., OIPC composite grains separated from the bulk OIPC composite). However, the capacity ratio of the 15 wt% sample was estimated to be between that of the 0 wt% sample and that of the 30 wt% sample at the same charge C rate. The addition of OIPC composite to the graphite anode improved the charge rate capability of the half cells.

[0145] [Table 6]

[0146] Consideration of the relatively low volume fraction of electrolyte in the graphite-[C2mpyr][FSI] composite anode - To show the same charge rate capability, the amount of transported ion salt required in the OIPC composite anode was evaluated to be less than that in the liquid electrolyte (Figure 4). The reason for the relatively low amount of electrolyte in the OIPC composite may be the presence of a liquid phase inside the OIPC composite, which is likely to occur during charge / discharge.

[0147] To understand this, we first calculated the amount of lithium ions required to fully lithiate the graphite and the amount of lithium ions in the PVdF fibers with OIPC composite. If the capacity is 0.246 mAh (estimated based on the active material ratios in Table S1 and the loading of the solid graphite anode without the OIPC composite, and the capacity of the graphite of 340 mAh / g), we can equate this value to Faraday's constant (96,485 A s mol -1 ) to fully lithiate graphite, + Amount of ions (9.2 x 10 -6 However, the amount of lithium ions in the PVdF fiber is 2.0×10 -6 mol (PVdF fiber thickness: 100 μm, PVdF fiber area: 0.503 cm 2 , and the tabulated information in Table 7). This means that more lithium ions are released from the lithium metal during charging.

[0148] [Table 7]

[0149] Conclusion of Example 1 - OIPC binder for graphite anode - Incorporating [C2mpyr][FSI] composite into graphite anode demonstrated a promising approach to enhance the charge rate capability and cycle life of ASSB. The effect of OIPC composite ratio inside the electrode on the charge-discharge profile and anode structure was systematically investigated by cell testing, SEM, EDX, and EIS. Half-cells containing either solid graphite anode or graphite-[C2mpyr][FSI] composite anode, electrospun PVdF fibers filled with [C2mpyr][FSI] composite, and lithium metal showed relatively large irreversible capacity at the first charge, while the coulombic efficiency gradually improved with increasing cycle number. The charge rate capability improved with increasing internal OIPC composite ratio, becoming comparable to that of the graphite anode with liquid electrolyte (85.7%, 295.9mAh / g at 2C charging) at 50wt% (charge capacity ratio: 89.5%, 295.7mAh / g at 2C charging). This improvement was explained as a structural difference of the solid graphite-[C2mpyr][FSI] composite anode. As the amount of OIPC composite increased, good lithium ion conduction pathways were established in the anode where the graphite particles and carbon black were well covered with OIPC composite. The best cycle stability was measured for the solid graphite-[C2mpyr][FSI] composite anode with 30wt% OIPC composite ratio. Preconditioning took about 20 cycles to stabilize, after which the discharge capacity retention showed no obvious decreasing trend, reaching 102.7%, 257.4mAh / g at the 100th cycle. The results provide valuable insight into the structure–property relationships of graphite-[C2mpyr][FSI] composite anodes, thereby laying a solid foundation for the development of ASSBs using OIPC composites.

[0150] Example 2 OIPC as a binder in conversion material electrodes The examples shown describe a new class of conversion reaction electrodes based on redox couples / centers, which contain an ionic binder in the form of an OIPC or OIPC complex as described herein in the electrode. The described conversion reaction material electrodes are particularly suitable for solid-state batteries. It is believed that the conversion reaction material electrodes described herein can mitigate undesired reactions between the electrolyte and the conversion material active material. In addition, it is believed that the OIPC improves the interfacial contact between the electrode / electrolyte and / or the electrode / current collector. The OIPC acts as a novel class of ionic binder for conversion reaction electrodes. The OIPC was introduced into the solid-state system to improve the interfacial adhesion between the electrode layer and the solid electrolyte, while also improving the ionic conductivity of the resulting electrode.

[0151] In some preferred cases, but not necessarily in all cases, new phases may form in the solid electrode composition upon mixing the OIPC or OIPC complex with a conversion reaction material (e.g., a transition metal material). It is believed that the phase transformation associated with the preferred electrode composition resulting from the inclusion of the OIPC allows for a reversible change in the phase composition and distribution of the composite electrode when an electrochemical potential is applied. It is further believed that the new phases may solvate or otherwise incorporate the redox couple material present in the electrode composite to facilitate ionic transport of charge carriers present and / or facilitate conversion transfer to and from the redox center.

[0152] Preferably, the conversion reaction material electrode is a cathode. The preferred solid electrode composition of the present invention can be easily formed into a coating and is therefore amenable to thin film processing techniques. The present material is believed to represent the first use of OIPC in the production of conversion materials for at least Li and Na batteries.

[0153] Examples of OIPC conversion material cathodes A number of examples of illustrative transition metal salt redox-active materials are provided below, including several conversion reaction materials.

[0154] Conversion cathode example A Fe(BF4)2·6H2O is used in combination with a series of different OIPC and inorganic lithium salts as described to form a number of novel OIPC cathode materials. Graphene is included in the OIPC cathode materials as a typical conductivity enhancing additive, however, any suitable conductivity enhancing additive known in the art can be used. In the experiments reported herein, the fraction of the conductive additive (graphene) is varied. The novel OIPC cathodes were then tested in cells containing a Li metal anode, a solid poly(IL) electrolyte membrane (described below). The results are shown below in Table 9.

[0155] The exact nature of the phases and compositions formed is under investigation, but for a complex containing Fe(BF4)2·6H2O, C2mpyrBF4, and LiBF4, the generalized reaction can be considered as follows: Li + +e - =Li 0 [C2mpyr + ][Fe 2+ ][BF4] B [Li + ]=[C2mpyr + ][Fe 3+ ][BF4] B +[Li + ]+e -

[0156] [Table 8]

[0157] Electrochemical characterization - The electrochemical behavior of Fe(BF4)26H2O and various OIPC / Li salt complexes was investigated. Sample F6 (Fe(BF4)26H2O-C2mpyrBF4 / LiBF4-graphene) is shown as the main example. Figure 9a-d shows the SEM images of Fe(BF4)26H2O, C2mpyrBF4 and the final cathode material. Comparing the XRD patterns of pristine Fe(BF4)26H2O and C2mpyrBF4 / LiFSI (Figure 9e), no new characteristic peaks appear in the XRD spectrum of Fe(BF4)26H2O-C2mpyrBF4-LiFSI (Fe-PBL). This indicates that the structures of both Fe(BF4)26H2O and C2mpyrBF4-LiFSI maintain their structures after mixing. When graphene was added as an electronic conductor to the Fe(BF4)26H2O-C2mpyrBF4-LiFSI mixture to prepare an electrode composite named Fe(BF4)26H2O-C2mpyrBF4-LiFSI-graphene, the peak of Fe(BF4)26H2O-C2mpyrBF4-LiFSI became broader. o , 7.9 o , 8.9 o , 9.4 o and 13.9 o Some peaks at 12.1 even disappear. o These results suggest that the addition of graphene can change the crystal structure of Fe(BF4)26H2O to some extent.

[0158] The cyclic voltammogram (CV) of the Fe(BF4)2×6H2O-C2mpyrBF4-LiFSI-graphene electrode is shown in Figure 10a. There are two sets of oxidation and reduction peaks at 2.0–4.0 V. When the scan rate is 0.1 mV / s, the two-step oxidation and reduction peak potentials are 2.59 / 2.28 V and 3.28 / 3.08 V, respectively. The theoretical specific capacity of Fe(BF4)26H2O is 158.8 mAhg based on the proposed two-electron electrochemical reaction. -1 It is.

[0159] A comparison of the rate capabilities of the cathode Fe(BF4)26H2O-C2mpyrBF4-LiFSI-graphene with OIPC as binder and the cathode using the commercial binder CMC (Fe(BF4)2×6H2O-CMC-LiFSI-graphene) is shown in Figure 10b. The cells were cycled at different current densities from C / 20 to 2C within the voltage range of 2.0–4.2 V at 50 °C. The SSIB using Fe(BF4)26H2O-CMC-LiFSI-graphene as the cathode produced 7.8 mAhg at a current rate of C / 20. -1 It can be seen that only a discharge capacity of 0.4 mg / cm can be achieved. Clearly, the capacity of Fe(BF4)26H2O-C2mpyrBF4-LiFSI-graphene is much larger than that of Fe(BF4)26H2O-CMC-LiFSI-g graphene at all C-rates tested. 2 The first cycle of the Fe(BF)26H2O-C2mpyrBF4-LiFSI-graphene composite achieved 120 mAhg at C / 20. -1 , 80mAhg at C / 10 -1 , 64mAhg at C / 5 -1 , 55mAhg at 1C -1 , 42mAhg at 2C -1 A high capacity was obtained.

[0160] When the charge / discharge rate goes back to C / 20, the capacity is 78mAhg -1 Returning to Fig. 10d, the discharge capacity decreases with increasing current rate, which may be related to the polarization. Figure 10d shows the corresponding galvanostatic discharge / lithiation and charge / delithiation curves of the first cycle of the Fe(BF4)2·6H2O-C2mpyrBF4-LiFSI-graphene composite electrode at different C-rates, showing that the average voltage plateau is around 3.2 V at all C-rates. The initial discharge capacity at C / 20 achieved 82% of the theoretical specific capacity and remained constant at half the theoretical specific capacity. From this result, we can conclude that only the second-stage lithium ion reaction (3.28 / 3.08 V) is reversible.

[0161] Compared to Fe(BF4)26H2O-CMC-LiFSI-graphene, Fe(BF4)26H2O-CmpyrBF4-LiFSI-graphene experiences lower interfacial resistance due to the soft interface contact between the electrode and solid electrolyte (Figure 10c). OIPC not only acts as a binder for the cathode to produce a soft interface, but also promotes fast diffusivity of lithium ions in the cathode. These results indicate that battery performance can be significantly improved by utilizing an optimal battery structure constructed using a soft interface between the cathode and electrolyte.

[0162] Electrolyte effect - By changing the electrolyte to PVDF-C2mpyrBF4 / LiFSI, the voltage range can be extended to 4.6V, and the battery capacity is about 110mAhg for over 50 cycles at 0.05C. -1 When the OIPC electrolyte PVDF-C2mpyrBF4 / LiFSI was used, the current was 160 mAhg -1 Unlike the Fe(BF4)26H2O-C2mpyrBF4-LiFSI-graphene electrode, which has a high specific capacity of over 1000 kV, the Fe(BF4)2×6H2O-CMC-LiFSI-graphene cell fails when charged to 4.6 V (Figure 11). Similarly, when the Fe(BF4)26H2O-CMC-LiFSI-graphene electrode was used with a related ionic liquid electrolyte, C3mpyrFSI / LiFSI(liquid), which has similar electrochemical stability and conductivity as the PVDF powder / C2mpyrFSI / LiFSI(solid) electrolyte (Figure 14), the cell failed immediately, likely due to dissolution of the electrode components in the ionic liquid solvent in this case.

[0163] This result indicates that the OIPC used in the electrolyte can affect the performance of the battery. In some embodiments, in preferred cells, the lithium salt used in the electrolyte and the lithium salt used in the electrodes have different counter anions. In other embodiments, the anions are the same.

[0164] Abstract - Experiments show that new OIPC electrode materials based on the conversion reaction material Fe(BF4)26H2O can be prepared. The performance of the OIPC electrode material can be tuned by the formulation of the composite matrix, including the choice of OIPC / salt, conductive filler, and the ratio of OIPC and salt used. Furthermore, the cell can also use the choice of solid electrolyte to tune the performance. Notably, the described OIPC solid electrodes are easily formed into coatings and are therefore applicable to thin film processing techniques.

[0165] Conversion cathode example B To demonstrate the versatility of the above conversion electrode composition, a similar cell was prepared using a sodium metal anode and with NaFSI salt incorporated (replacing LiFSI) (Figure 13). Using a similar OIPC electrolyte (PVDF powder / CmpyrFSI / NaFSI), the Fe(BF4)26H2O-CmpyrBF4-NaFSI-graphene cell produced 120 mAhg -1 It can be seen that it exhibits stable performance at average discharge voltages near and 3.2 V. This example highlights the use of OIPC conversion electrode materials with alternative transport metal ions and corresponding anode chemistries and demonstrates the broad application of the new OIPC electrode materials.

[0166] Conversion cathode example C Other conversion electrode materials such as metal halides, metal oxides, metal sulfides, etc. can also be dispersed within the OIPC matrix. It is believed herein that the active materials remain as separate phases within the OIPC / salt complex. Thus, the mechanism may be distinctly different from the iron example above. However, without the OIPC binder, these electrodes would not exhibit cycling behavior.

[0167] CuF2 / C2mpyrBF4 / LiBF4 / graphene cathodes and CuF2 / PVDF / LiBF4 / graphene cathodes were prepared and a comparison of the cell performance is shown in Figure 15. Excellent capacity and stability are shown when OIPC is incorporated within the electrode. In these examples, it is believed that the optimal combination and composition of OIPC, Li salt, and conversion electrode material (CuF2) was not obtained to stabilize the cycling performance. Table 10 shows alternative combinations of CuF2 conversion electrode material with different OIPC, binder, Li salt, and solid electrolyte compositions and the electrochemical performance obtained with each composition. The dependence of the cell performance on each of the components is clearly shown.

[0168] [Table 9]

[0169] Conversion cathode examples D and E To further demonstrate the breadth of the new OIPC electrode materials using different conversion electrode materials, alternative conversion cathode materials were prepared using the same method and general composition. OIPC electrolyte and OIPC electrode materials are used to demonstrate the utility of conversion electrode active material capacity in the solid state. The cell performance data shown in Table 11 shows results for a general composition of active material (FeCl3, Fe triflate, CoCl2, CoTFSI, CoF3) 80 wt%, graphene 5 wt%, OIPC 9 wt%, and Li salt 6 wt%. In each case, the active material is shown to function, but with varying degrees of capacity fade after subsequent charge / discharge cycling. In this case, the limited range of compositions tried requires further optimization to improve utility and cycling stability, but the utility and functionality of OIPC to enable ASSB using conversion electrode type materials has been demonstrated. Figure 16 highlights the use of the new OIPC electrode material with the novel metaphosphate cathode material, Ni(PO3)2 (see, for example, ChemElectroChem 2020, 7, 2831), and shows a comparison with an electrode without OIPC binder, highlighting the improved capacity and stability brought by the C2mpyrFSI OIPC binder. A high capacity of 205 mAh / g is obtained at the second cycle with the cathode containing OIPC as binder, which is much higher than the capacity of the cathode using the commercial binder CMC (43 mAh / g). After 100 cycles, the capacity of the cathode with OIPC still remains at 32 mAh / g, while the capacity of the cathode without OIPC remains only 0.5 mAh / g. Table 12 shows the dependence of the cycling performance of Ni(PO3)2 on the electrode loading, again showing the improved performance contributed by OIPC in the absence of OIPC (sample N3).

[0170] [Table 10]

[0171] [Table 11]

[0172] Considerations regarding OIPC binders for conversion electrode materials: - The experiments reported herein show that conversion electrode materials (e.g., Fe(BF4)26H2O, CuF2, CoF3, FeCl3, Fe triflate, CoCl2, CoTFSI, CoF3, etc.) can be prepared and formulated as OIPC cathodes that support charging and discharging for at least 50 cycles of cycling. The battery performance is related to the properties of the composite matrix, which can be tuned by the selection of OIPC / salt, conductive filler, and the ratio and amount of components used.

[0173] Some compositions yielded high initial specific capacitances (e.g., CoCl26H2O-C2mpyrFSI / LiFSI). However, unlike the favorable phase composition formed from Fe(BF4)26H2O, where DSC indicated salt dissolution within the OIPC matrix, the conversion electrode compositions tended to exhibit capacity fade.

[0174] Nonetheless, these examples demonstrate that dispersion of conversion active materials within an OIPC matrix shows promise in enabling solid-state electrodes with good capacity and stability. The 3-4 V devices described herein can be optimized to achieve theoretical specific energy (e.g., 477 Wh / kg for the Fe(BF4)26H2O example), high thermal and cycling stability, and safe all-solid-state batteries.

[0175] To improve conversion electrodes, we demonstrate here that OIPC electrode design is an effective approach to bring promising performance to ASSBs. Conversion electrodes containing transition metal salts with anions from the oxygen, halogen, chalcogenide, or pnictide groups have attracted attention due to their high theoretical specific capacity. At the same time, the scope of known OIPCs has been steadily broadened, and great progress has been made toward superior electrochemical performance, such as increased ionic conductivity, improved stability, and increased transport number.

[0176] New OIPCs have been discovered and intensively studied, including pyrrolidinium, imidazolium, phosphonium, guanidinium, oxazolidinium and metallocenium cations with various anions such as tetracyanoborate, tetrahalogenoferrate(III), camphorsulfonate and nonaflate. The OIPC electrode strategy opens new fields for developing advanced electrodes based on a broad range of OIPC families and conversion electrode materials. The strategies revealed herein in the field of cathode materials may also be applied to anodes, with the potential to further broaden the scope of sodium batteries as well as improve the battery electrode library. This pioneering work in the field of organometallic ion hybrid electrodes and beyond, and a guide to future energy metrics to progress towards practical implementation, as well as in terms of developing novel materials, offers many possibilities for chemical and structural modifications to further increase redox potentials along with storage capacity and improve cycling stability in the search for practical high energy batteries.

[0177] Example F Intercalation-type layered oxides and OIPC binders in polyanionic cathodes. OIPC was used as a binder for LiFePO4 cathode materials in the form of OIPC mixed ionic electronic conductor (MIEC) polymer composite binder. An exemplary MIEC polymer used in the OIPC binder composite herein is PEDOT:PSS, which was found to have excellent ionic and electronic conductivity. OIPC composite binders with 80 / 20 ratio PEDOT:PSS / C2mpyrFSI composites were selected for testing in battery cells as electronic and ionic conductive binders. Due to the high electronic and ionic conductivity of the composites, as well as good mechanical properties, they were applied as conductive binders in solid-state lithium-ion batteries. Cycling of solid-state batteries requires a certain source of lithium ions in the electrode to aid in the discharge of the cathode. Since good interactions between LiFSI salt and C2mpyrFSI OIPC have already been reported, which further leads to high ionic conductivity, the 80 / 20 PEDOT:PSS / C2mpyrFSI composite was selected for battery applications to maintain ionic compatibility. The excellent ionic and electronic conductivity of this OIPC-MIEC composite implied that the electrode could be a carbon-free electrode. A solid-state Li|LiFePO4 cell was prepared containing the OIPC composite as a cathode binder. Considering that solid-state battery electrodes typically contain 60 wt% active material, the following formulation was proposed and characterized: LFP 60%, 80 / 20 PEDOT:PSS / C2mpyrFSI composite 35%, and LiFSI 5%. A previously studied ternary polymer electrolyte system (PILBLOC) based on poly(ionic liquid) block copolymer, N-methyl-N-propylpyrrolidinium bis(fluorosulfonyl)imide (C3mpyrFSI) ionic liquid, and LiFSI showed good compatibility with lithium metal and a current density of 0.20 mA cm. -2Poly(ionic liquid) was used as the solid electrolyte because of its stable cycling performance up to 1000 s (see U.S. Patent Application 16 / 649,753, 2020, Journal of The ElectroChemical Society 167(7), 070525). The cells were tested by galvanostatic charging and discharging using poly(ionic liquid) solid electrolyte. The solid Li|LiFePO4 cell with OIPC-MIEC binder showed improved discharge capacity (156 mAh g at C / 10) compared to the cell with ionically conductive binder. -1 ) and rate capability (Figure 17). -1 A specific capacity of 130 mAh g at C / 2 and 70 °C was achieved, with nearly 100% capacity retained after 70 cycles at 70 °C. The cell performance was comparable to that of the conventional ionically conductive binder (130 mAh g at C / 2 and 70 °C). -1 ) was superior to the OIPC binder in the form of an OIPC-MIEC complex. It is believed that the OIPC binder provides superior electronic-ionic interconnects in non-porous electrodes for all-solid-state batteries. The measured electronic conductivity of the complex was C 65 Pellet (2.01±0.17Scm -1 , 583μm) was higher than that (469Scm -1 ). Increasing the C-rate up to C / 2 resulted in a larger overpotential as a result of diffusion limitations. This effect is much more pronounced for the PILBLOC electrode than for the 80 / 20 PEDOT:PSS / C2mpyrFSI cell, whose strongly polarized profile can be attributed to the capacitive nature of the binder and is responsible for reaching a high capacity density. A lower overpotential can be observed at C / 10 for both systems, and the higher capacity of the OIPC-MIEC binder can be attributed to a better electronic interconnection within the electrode, which is generally seen when electronically conducting polymers are used in the electrode formulation. A summary of the obtained values ​​is listed in Table 11 and compared with the reported performance of similar cells. The performance obtained with the P:PSS / C2mpyrFSI binder is very promising, suggesting high Li for the active material in a non-porous configuration. + The ability of the PEDOT:PSS / OIPC composite to behave both as a donor and as an excellent electronic conductor is confirmed.

[0178] [Table 12]

[0179] A further example is 1.1 mAhcm -2 The OIPC binder was combined with a LiFePO4 intercalation electrode (Figure 19, Figure 20), and a Li2MnO4 intercalation electrode (Figure 21) at higher electrode loadings of 10 ... -1 , and retained 84.5% of the initial discharge capacity. These results highlight the use of OIPC binders in conventional electrode formulations as well as their effective use in ASSBs using conventional electrode thin film processing techniques and binders and conductive additives.

[0180] Experimental Section Materials: Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (Clevios PH 1000) at 1.3 wt.% solids in water was supplied by Heraeus Inc. N-Ethyl-N-methylpyrrolidinium bis(trifluoromethylsulfonylimide) (C2mpyrTFSI) (99%) was purchased from IoLiTec and N-Ethyl-N-methylpyrrolidinium bis(fluorosulfonylimide) (C2mpyrFSI) was synthesized as previously reported.

[25] N-propyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide (C3mpyrFSI, 99.5%) was supplied by Solvionic. Lithium iron phosphate (LiFePO4) (ALEEES) and SuperC65 (Timcal). 1-Methyl-2-pyridinone (NMP) (99.5%) was purchased from Sigma Aldrich. PILBLOC polymer was obtained similarly to previously reported work. See US Patent Application 16 / 649,753, 2020 and Journal of The Electrochemical Society 167(7), 070525, the contents of which are incorporated by reference.

[0181] Solid electrolyte: Cathode preparation: A mixed conductive binder-LiFePO4 system slurry was prepared by first dispersing freeze-dried PEDOT:PSS, CMPyrFSI, and LiFSI in DMSO, and finally dispersing active material powders with a weighted ratio of 60 / 28 / 7 / 5 (LiFePO4 / PEDOT:PSS / CMPyrFSI / LiFSI). The PILBLOC-LiFePO4 electrode was prepared by dispersing the corresponding weighted ratio of 60 LiFePO4 / 10 C in NMP. 65 The cathode was obtained by mixing the optimized PILBLOC (LiFSI: 2 mol; C3mpyrFSI: 1 mol) from our previous study with 1000 / 30 PILBLOC. The prepared slurry was cast on a carbon-coated aluminum current collector by using a doctor blade, dried at room temperature and finally dried overnight at 60 °C under vacuum. No liquid electrolyte was used to wet the cathode since the ionic conduction of lithium was ensured by the use of the mixed conductor binder and lithium salt. The mass loading of the obtained electrode was 1.2 mg cm for both systems. -2 It was.

[0182] Cell characterization: Li|LiFePO4 cells (CR2032) were assembled in an argon glove box using 50 μm lithium foil. Galvanostatic cycling was performed using a battery tester (Neware) at 70 °C, the optimum temperature for the electrolyte.

[0183] Example G OIPC Binders in Silicon Anodes Silicon anodes containing the [C2mpyr][FSI] composite binder described here were prepared and their cell performance was compared with that of a Si anode containing a liquid electrolyte binder (LP30 - 1 M LiPF6 in EC-DMC (1:1 vol%)).

[0184] The Si / [C2mpyr][FSI] electrode was used with a PVdF / [C2mpyr][FSI] OIPC interlayer and a lithium metal anode as described elsewhere herein. The Si / [C2mpyr][FSI] composite anode electrode has the following Si:carbon black:Na-CMC:[C2mpyr][FSI]:LFSI contents: 59.5 wt%:12.8 wt%:9.2 wt%:5.8 wt%. The Si / [C2mpyr][FSI] composite anode has a Si:carbon black:Na-CMC:[C2mpyr][FSI]:LFSI content of 0.22-0.28 mg / cm 2 and densities of 0.20-0.43 g / cm3. The Si electrodes were used with LP30 electrolyte and Celgard 3501 separator, and lithium metal anode as described elsewhere herein. The Si anode was used with the following: 70:15:15 wt% Si:carbon black:Na-CMC content. Test conditions were as follows: charge - 0.07 V, 0.02 C-CC; discharge - 1.0 V, 0.02 C-CC; rest - 10 min between charge and discharge; temperature - 50°C.

[0185] The charge-discharge profiles are shown in Figure 18. The thin coating introduced errors into the determined specific capacitance values, resulting in larger than theoretical specific capacitance values. However, the coatings were obtained by the same process, so comparisons between cells are valid. The performance of the OIPC binder electrodes was shown to be generally consistent with that of the liquid electrolyte, and both electrodes show relatively rapid capacity fade with cycling, a well-known issue with high utilization cycling of Si anodes. The OIPC / Si electrode showed a first cycle efficiency of 79.4% and a capacity of 5879 mAhg by the fifth cycle.-1 In comparison, the Si anode without OIPC showed a first cycle efficiency of 78.6% and 4975 mAhg by the fifth cycle. -1 (59.7% retention). The results show that the performance of the ASSB Si / OIPC electrode can match that of a liquid cell using a commercial electrolyte.

Claims

1. An electrochemical energy storage device comprising at least one pair of a positive electrode and at least one negative electrode, wherein at least one electrode is - Particles of an electrochemically active material; - Particles of an optional electronically conductive additive; - Particles of an optional non-ionically conductive polymer binder; and - An internal ion binder in the form of a preformed intimate complex of an organic ion soft viscous crystal (OIPC) and a transport ion salt is a solid electrode in the form of a dry electrode composition, and most of the voids between the particles are completely or partially filled with concentrated or discrete portions of the preformed intimate complex, an electrochemical energy storage device.

2. The voids between the particles that block the ion conduction path in the electrode are substantially filled with the internal ion binder in complex form, thereby removing the blockage of the ion conduction path in the electrode and / or increasing the ion conduction path. The device according to claim 1.

3. The dry electrode composition does not contain one or more of an ionically conductive polymer electrolyte or a monomer of an ionically conductive polymer electrolyte, an organic solvent, an ionic liquid other than OIPC, a polymerizable ionic liquid monomer and / or a polymerized poly(ionic liquid), an ionogel, a polyionic liquid ionogel and / or a polymerization initiator. The device according to claim 1.

4. Configured as an all-solid energy storage device, further comprising an ion transport intermediate layer disposed between each pair of the electrodes, the separated portions of the intermediate layer being in direct contact with each electrode of the pair, and the contact between the ion transport intermediate layer and each electrode including substantially void-free contact. The ion transport intermediate layer is an ion transport membrane incorporating one or more of OIPC, an ionic liquid, and an ion transport salt. The device according to claim 1.

5. The ion transport intermediate layer contains the same OIPC and ion transport salt as the OIPC and ion transport salt of the solid electrode. The device according to claim 4.

6. The ion transport intermediate layer is a polypropylene separator filled with a Li-doped ２ [Cmpyr][FSI] electrolyte, or a polypropylene separator filled with a Li-doped １２２２ [P][FSI] electrolyte, and the device according to claim 4 is a membrane.

7. The ratio of the OIPC to the transport ion salt in the complex is from about 9:1 to about 1:9 mol%, or from about 9:1 to about 1:9 wt%. The device according to claim 1.

8. The internal ion binder is present in an amount of at least about 15 wt% and not more than about 50 wt% of the total electrode composition. The device according to claim 1.

9. The internal ion binder is Is only the particles of the electrochemically active agent coated? Is only the particles of the conductivity improving additive contained in the electrode composition coated? The device according to claim 1, wherein the particles of the electrochemically active agent and the particles of the conductivity improver contained in the composition are coated simultaneously.

10. The device according to claim 1, wherein the ion transport salt is an alkali metal, an alkaline earth metal salt, or a transition metal salt.

11. One electrode of each electrode pair is a positive electrode (cathode) containing a positive electrochemically active material selected from a layered metal oxide; a polyanionic compound; sulfur; and a conversion reaction material containing a redox center, wherein the positive electrochemically active material includes a transition metal material selected from lithium cobaltate (LCO), lithium iron phosphate (LFP), lithium manganese phosphate (LMP), lithium nickel manganese cobaltate (NMC), and lithium nickel cobaltate (NCA) doped with alumina, lithium manganate (LMO), or the positive electrochemically active conversion reaction material containing a redox center is a transition metal ion-based redox couple selected from Fe 2+ / Fe 3+, Co 2+ / Co 3+, Ni 2+ / Ni 3+, Mn 2+ / Mn 3+ or Cu 2+ / Cu 3+, or the positive electrochemically active conversion reaction material containing a redox center is a transition metal ion-based redox couple containing Fe(BF 4)·6H 2 O, Fe(BF 4) 2.6H 2 O, Co(II)TFSI, Fe(II) triflate or Ni(PO 3) 2, and / or One electrode of each electrode pair is a negative electrode containing a negative electrochemically active material selected from hard carbon; graphite; silicon; lithium; sodium; iron; manganese; phosphorus; antimony; bismuth, selenium, lithium alloy. **Claim 12**: The electrochemically active material of the positive electrode (cathode) is selected from conversion reaction materials containing a redox center, and the conversion reaction material is a transition metal ion-based redox couple selected from Fe2+ / Fe3+, Co2+ / Co3+, Ni2+ / Ni3+, Mn2+ / Mn3+ or Cu2+ / Cu3+, or the positive electrochemically active conversion reaction material containing a redox center is a transition metal ion-based redox couple containing Fe(BF4)·6H2O, Fe(BF4)2·6H2O, Co(II)TFSI, Fe(II) triflate or Ni(PO3)2. The device according to claim 1. **Claim 13** The cation of the organic ion soft viscous crystal (OIPC) compound of the ion internal binder is [N １，１，１，１ , [N １，２，２，２ , [hexamethylguanidinium], [C ２ mpyr], [P １，２，２，２ , [P １，２，２，ｉ４ , [P １，４，４，４ , [H ２ im], [Hmim], [N ２，２，３，３ , [N ３，３，３，３ , [C ２ epyr], [C １ moxa][FSI], [C ２ mmor], [C １０１ mpyr], [C １ mpyr], [C ４ mpyr], [(NH ２ )( ３ , [2-Me-im], and [TAZm], and is selected from the group consisting of The anion of the organic ion soft viscous crystal (OIPC) compound of the ion internal binder is selected from the group consisting of [DCA], [BF₄], [TFSI], [FSI], [PF₆], [Tf], [BBu₄], [TCM], [DFTFSI], [FTFSI], [(FH)₂F], [PFBS], and preferably the OIPC is [N₁,₁,₁,₁][DCA], [N₁,₂,₂,₂][BF₄], [P₁,₂,₂,₂][TFSI], [hexamethylguanidinium][TFSI], [hexamethylguanidinium][BF₄], [hexamethylguanidinium][FSI], [C₂mpyr][BF₄], [C₂mpyr][FSI], [C₂mpyr][TFSI], [C₂mpyr][BF₄], [P₁,₂,₂,₂][FSI], [P₁,₂,₂,i₄][PF₆], [P₁,₄,₄,₄][FSI], [H₂im][Tf], [Hmim][Tf], [N₂,₂,₃,₃][BBu₄], [N₃,₃,₃,₃][BF₄], [C₂epyr][TFSI], [C₂epyr][FSI], [C₂epyr][PF₆], [C₂epyr][BF₄], [C₁moxa][FSI], [C₂moxa][FSI], [C₁moxa][TFSI] (oxa = oxazolidinium), [C₂mmor][FSI], [C₂mmor][TFSI], [C₂mmor][BF₄] (mor = morpholinium), [C₁₀₁mpyr][FSI], [C₂mpyr][TCM], [C₂mpyr][DFTFSI], [C₂mpyr][FTFSI], [C₁mpyr][(FH)₂F] and [C₂mpyr][(FH)₂F], [C₄mpyr][TFSI], [(NH₂)₃][Tf], [2-Me-im][Tf], and [TAZm][PFBS], and the device according to any one of claims 1 to 12.

14. A all-solid-state energy device comprising a pair of at least one positive electrode and at least one negative electrode, wherein the negative electrode is - Particles of an electrochemically active material selected from hard carbon, graphite; silicon; phosphorus; selenium; antimony; bismuth; lithium titanate, especially lithium alloys such as lithium titanate; or metal anode materials such as lithium metal and sodium metal; - Particles of an optional electron conductive additive; - Particles of an optional non-ion conductive polymer binder; and -C ２ mpyrBF ４ ; C ２ mpyrFSI; and C ２ An internal ion binder in the form of a preformed intimate complex with an organic ion plastic crystal (OIPC) selected from the group consisting of mpyrTFSI, LiFSI, LiBF ４ , LiTFSI, LiOTf ２ , NaFSI, NaBF ４ , NaTSI, NaTFSI, or NaOTf ２ and a transport ion salt selected from the group consisting of A all-solid energy device which is an alloying or insertion type solid negative electrode comprising a dry electrode composition containing the same.

15. At least one pair of a positive electrode and at least one negative electrode, and C disposed between each pair of the electrodes ２ mpyrBF ４ ; C ２ mpyrFSI; and at least one organic ion soft viscous crystal (OIPC) selected from the group consisting of C ２ mpyrTFSI, and an ion transport intermediate layer containing a transport ion salt selected from the group consisting of LiFSI, LiBF ４ , LiTFSI, LiOTf ２ , NaFSI, NaBF ４ , NaTSI, NaTFSI, or NaOTf ２ A all-solid energy device comprising an ion transport intermediate layer, wherein the separated portions of the intermediate layer are in direct contact with each electrode of the pair The negative electrode is - Particles of an electrochemically active material selected from hard carbon, graphite; silicon; phosphorus; selenium; antimony; bismuth; lithium titanate, especially lithium alloys such as lithium titanate; or metal anode materials such as lithium metal and sodium metal; - Particles of an optional electron conductive additive; - Particles of an optional non-ion conductive polymer binder; and - An internal ion binder in the form of a pre-formed intimate complex of an organic ion soft flexible crystal (OIPC) and a transport ion salt which is the same as the OIPC and transport ion salt of the ion transport intermediate layer A all-solid energy device which is an alloying or insertion type solid negative electrode comprising a dry electrode composition containing the same and not containing an ion conductive polymer electrolyte or a monomer of an ion conductive polymer electrolyte.

Images