Ion-electron dual continuous conductor cathode composite, solid-state cathode and lithium battery

Abstract

This application relates to an ion-electron dual continuous conductor cathode composite material, a solid-state cathode, and a lithium battery. The method includes: metal-organic framework particles with regular one-dimensional channels; a lithium salt electrolyte pre-filled within the one-dimensional channels, the lithium salt electrolyte forming continuous ion channels within the one-dimensional channels; a conductive polymer layer in situ polymerized on the outer surface of the metal-organic framework particles, the conductive polymer layer forming continuous electron channels on the outer surface of the metal-organic framework particles; and a cathode active material mechanically mixed with the metal-organic framework particles; wherein the continuous ion channels and the continuous electron channels are spatially isolated from each other and are continuous, so as to simultaneously provide ion transport paths and electron transport paths within the solid-state cathode. This application's embodiments achieve, for the first time, the continuity and spatial isolation of ion channels and electron channels within a single composite particle, significantly reducing the dual-channel percolation threshold and improving interface compatibility.

Description

Technical Field

[0001] This application belongs to the field of all-solid-state lithium battery technology, and particularly relates to ion-electron dual continuous conductor cathode composite materials, solid cathodes and lithium batteries. Background Technology

[0002] Solid-state lithium batteries are considered the next-generation energy storage technology due to their combination of high energy density and high safety; however, existing technologies generally face solid-solid contact bottlenecks. Existing technology CN111082128A uses a mixture of sulfide fast-ion conductors and conductive agents to prepare the positive electrode. Although this modifies ion / electron channels at the atomic scale, the spontaneous in-situ generation method leads to a significant decrease in battery consistency. Under high-rate charge-discharge conditions, the polarization of the solid-state battery's positive electrode, electrolyte, and negative electrode all increase sharply, resulting in rapid capacity decay and limiting electrode loading to 3 mAh / cm³. -2 The following factors severely restrict the commercialization of solid-state batteries. Summary of the Invention

[0003] This application provides an ion-electron dual continuous conductor cathode composite material, a solid cathode, and a lithium battery to solve the following technical problem: how to simultaneously construct a continuously isolated ion-electron dual transport channel within a solid cathode.

[0004] In a first aspect, embodiments of this application provide an ion-electron dual continuous conductor positive electrode composite material, comprising:

[0005] Metal-organic framework particles with regular one-dimensional channels; A lithium salt electrolyte pre-filled within the one-dimensional channel, wherein the lithium salt electrolyte forms a continuous ion channel within the one-dimensional channel; A conductive polymer layer in situ polymerized on the outer surface of the metal-organic framework particles, the conductive polymer layer forming continuous electron channels on the outer surface of the metal-organic framework particles; and Positive electrode active material mechanically mixed with the metal-organic framework particles; The continuous ion channel and the continuous electron channel are spatially isolated from each other and are continuous, so as to provide both ion transport path and electron transport path in the solid cathode.

[0006] Optionally, the metal-organic framework is at least one of ZIF-8, MIL-101(Cr), UiO-66-(OH)2, UiO-66-(COOH)2, Mg-MOF-74 or Ni-MOF-74.

[0007] Optionally, the pore size of the metal-organic framework particles is slightly larger than that of desolvated Li. + Diameter, to achieve desolvation of Li + Size-selective transmission.

[0008] Optionally, the metal-organic framework particles contain unsaturated metal sites that anchor lithium salt anions to increase the lithium ion transference number.

[0009] Optionally, the surface of the metal-organic framework particles has -OH or -COOH functional groups, which are covalently grafted to the conductive polymer layer.

[0010] Optionally, the lithium salt electrolyte is selected from at least one of LiPF6, LiTFSI, LiDFP, LiDFOB, LiTFS, LiBF4, Li3PS4, Li6PS5X or Li2S, wherein X is Cl, Br or I.

[0011] Optionally, the lithium salt electrolyte exists in the one-dimensional channel in a high-concentration loading manner to form a locally high ionic conductivity environment within the one-dimensional channel.

[0012] Optionally, the conductive polymer layer is at least one of PEDOT-b-PEO block copolymer, self-doped polyaniline derivative SPAN, or PEDOT derivative containing sulfonic acid groups.

[0013] Optionally, single-walled carbon nanotubes are synchronously composited within the conductive polymer layer, and the single-walled carbon nanotubes form a three-dimensional conductive network within the conductive polymer layer.

[0014] Optionally, the thickness of the conductive polymer layer is ultrathin, which is formed directly by in-situ oxidative polymerization, and the specific value range of the ultrathin layer is 2nm to 500nm.

[0015] Optionally, the positive electrode active material is NCM811.

[0016] Optionally, the composite material has a positive electrode area loading of ≥4 mAh / cm². 2 At the same rate, the capacity retention is ≥90% at 1C and ≥80% at 2C. The electronic conductivity of the composite material decreases by less than 10% after 500 cycles.

[0017] Secondly, embodiments of this application provide a solid positive electrode comprising the ion-electron dual continuous conductor positive electrode composite material, a conductive agent, and a binder as described in any of the first aspects.

[0018] Thirdly, embodiments of this application provide an all-solid-state lithium battery, including the solid positive electrode, solid electrolyte, and negative electrode described in the second aspect.

[0019] Optionally, the solid electrolyte is a sulfide fast ion conductor xLi2S-(1-x)P2S5, where x=0.6-0.8.

[0020] The technical solutions provided in this application have the following advantages compared with the prior art: Because competition and spatial overlap of ion-electron transport paths in solid-state cathodes lead to interfacial polarization and capacity decay, this application first constructs regular one-dimensional channels within metal-organic framework (MOF) particles. Utilizing the uniform pore size and chemically modifiable pore walls of MOF particles, lithium salt electrolyte is pre-filled into these channels. Since the channels are rigid and continuously interconnected, the lithium salt electrolyte forms continuous ion channels extending axially along the channels within the confined space, thereby allowing the lithium salt electrolyte inside the cathode to transport ions. + The transport process shifts from random diffusion to directional migration, thereby eliminating the ion concentration gradient caused by grain boundary blockage. Simultaneously, the outer surface of MOF particles is rich in open metal sites and ligand functional groups, which can act as redox active sites to initiate in-situ polymerization of conductive monomers. This allows the conductive polymer layer to be anchored to the particle surface in a conformal coating manner. Since the polymer layer is only tens of nanometers thick and overlaps with each other, a continuous three-dimensional electron channel is formed between the MOF particles, efficiently delivering electrons from the current collector to each MOF-active material interface, thus reducing interfacial charge transfer resistance. Subsequently, the continuous ion channel is located inside the MOF pores, and the continuous electron channel is located outside the MOF particles. These two channels are spatially physically isolated by the MOF framework walls and remain continuous, thus avoiding parasitic side reactions (such as polymer oxidation by high-valence metals or lithium salt reduction by electrons) that occur when electrons and ions transport along the same path. This simultaneously increases ion and electron flux without sacrificing interfacial stability. Finally, the MOF-electrolyte-conductive polymer composite particles are mechanically mixed with the positive electrode active material. The surface of the active material particles and the conductive polymer layer form point-to-surface contact, allowing electrons to quickly reach the active material through the polymer layer. At the same time, the gaps between the active material particles are filled with lithium ions escaping from the MOF channels, and the ions can be quickly replenished through the channel-particle interface. This simultaneously constructs a "dual continuous but spatially isolated ion-electron" transport network on the entire solid-state positive electrode scale, thereby solving the technical problems of large polarization, poor rate capability, and short cycle life caused by the overlap of ion-electron transport paths in solid-state electrodes.

[0021] Compared with the shortcomings of existing technologies that "simplely blend conductive agents and solid electrolytes at the electrode level" leading to channel crossover, interfacial side reactions, and high percolation thresholds, the embodiments of this application utilize a synergistic strategy of MOF regular pore confinement and outer surface polymerization to achieve, for the first time, continuous and spatially isolated ion channels and electron channels within a single composite particle, significantly reducing the dual-channel percolation threshold and improving interfacial compatibility. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] The range descriptions used herein, such as numerical ranges and proportional ranges, include all possible sub-ranges and single numerical values ​​within that range. For example, the range descriptions of "1 to 6" or "1~6" cover all sub-ranges (such as 1 to 3, 2 to 5, etc.) and single numbers (such as 1, 2, 3, 4, 5, 6) between 1 and 6. Unless otherwise specified, the terms "including" and "contains" as used herein mean "including but not limited to"; relational terms such as "first" and "second" are used only to distinguish different entities or operations and do not imply an actual order or relationship; "and / or" indicates that multiple situations can exist individually or simultaneously; expressions such as "at least one," "multiple," and "at least one" refer to any combination of the corresponding objects, including combinations of single or multiple objects. The proportional relationships mentioned herein, such as mass ratios and molar ratios, should be understood as the correspondence between the first and second terms of a proportional formula, according to the order of description. The raw materials, reagents, instruments, and equipment used herein can all be obtained through commercial purchase or prepared using existing methods.

[0024] In a first aspect, embodiments of this application provide an ion-electron dual continuous conductor positive electrode composite material, comprising: S1, Metal-organic framework particles with regular one-dimensional channels; S2. A lithium salt electrolyte pre-filled in the one-dimensional channel, wherein the lithium salt electrolyte forms a continuous ion channel in the one-dimensional channel; S3. A conductive polymer layer in situ polymerized on the outer surface of the metal-organic framework particles, wherein the conductive polymer layer forms continuous electron channels on the outer surface of the metal-organic framework particles; and S4. Positive electrode active material mechanically mixed with the metal-organic framework particles; The continuous ion channel and the continuous electron channel are spatially isolated from each other and are continuous, so as to provide both ion transport path and electron transport path in the solid cathode.

[0025] "Ion-Electron Dual Continuous Conductor Cathode Composite Material": refers to a solid-state cathode functional body composed of metal-organic framework particles, lithium salt electrolyte, conductive polymer layer, and cathode active material, containing both spatially isolated and continuous ion and electron channels. "Regular One-Dimensional Channels": refer to cylindrical or near-cylindrical channels within the metal-organic framework particles that are continuous along crystallographic directions, have uniform pore size, and ordered pore wall structure, used to define the filling space of the lithium salt electrolyte. "Continuous Ion Channels": refer to unbroken ion conduction paths within the regular one-dimensional channels of the lithium salt electrolyte. "Continuous Electron Channels": refer to unbroken electron conduction paths guiding the polymer layer across the outer surface of the metal-organic framework particles. "Mutual Isolation": means that the continuous ion channels are located inside the regular one-dimensional channels, and the continuous electron channels are located on the outer surface of the metal-organic framework particles, with no direct spatial contact between the two.

[0026] Metal-organic framework (MOF) particles provide regular one-dimensional channels, which are pre-filled with lithium salt electrolyte. The lithium salt electrolyte forms continuous ion channels within these channels, providing a continuous lithium-ion transport path for the positive electrode active material. A conductive polymer layer is in-situ polymerized on the outer surface of the MOF particles, forming continuous electron channels and providing a continuous electron transport path for the positive electrode active material. The continuous ion channels and continuous electron channels are spatially isolated and continuous, allowing for the parallel existence of ion and electron transport paths within the same solid-state positive electrode. The positive electrode active material is mechanically mixed with the MOF particles, simultaneously contacting both the continuous ion and electron channels. This solves the problem of discontinuous ion and electron transport channels caused by poor solid-solid contact within the solid-state positive electrode, thus achieving "how to simultaneously construct continuous and isolated ion-electron dual transport channels within a solid-state positive electrode." This application, for the first time, establishes independent and continuous ion and electron channels simultaneously in a single positive electrode functional body through spatial partitioning, overcoming the limitation of traditional mixing and polishing methods that cannot simultaneously achieve continuous ion and electron transport.

[0027] In some embodiments, the metal-organic framework is at least one of ZIF-8, MIL-101(Cr), UiO-66-(OH)2, UiO-66-(COOH)2, Mg-MOF-74, or Ni-MOF-74.

[0028] The metal-organic framework particles are selected from at least one of ZIF-8, MIL-101(Cr), UiO-66-(OH)2, UiO-66-(COOH)2, Mg-MOF-74, or Ni-MOF-74, thereby providing a crystal framework with regular one-dimensional channels. The interior of this crystal framework can be pre-filled with lithium salt electrolyte to form continuous ion channels, and the outer surface can be in-situ polymerized with a conductive polymer layer to form continuous electron channels, thus realizing "how to simultaneously construct continuous and isolated ion-electron dual transport channels within a solid cathode." This application utilizes the differences in pore size and chemical stability of different metal-organic framework particles to provide diverse carrier options for the synergistic construction of continuous ion channels and continuous electron channels.

[0029] In some embodiments, the pore size of the metal-organic framework particles is slightly larger than that of desolvated Li. + Diameter, to achieve desolvation of Li + Size-selective transmission.

[0030] Desolvation of Li + "Diameter": refers to the effective diameter of the bare lithium ion formed after the lithium ion completely loses its solvation shell in the electrolyte. In the embodiments of this application, it is regarded as the size of a rigid sphere less than 3.4 Å, and is used for comparison with the size of a regular one-dimensional channel opening.

[0031] The pore size of the metal-organic framework particles is slightly larger than that of desolvated Li. + The diameter of the pores allows for size-selective transport of desolvated Li+ ions. This size-selective transport reduces the entry of anions or byproduct molecules into the regular one-dimensional channels, thereby increasing the lithium-ion transference number. Increased lithium-ion transference number reduces concentration polarization, further enhancing the ion transport capability of continuous ion channels. This, in conjunction with continuous electron channels, enables the simultaneous construction of continuously isolated ion-electron dual transport channels within a solid-state cathode. In this application, embodiments utilize a pore size matching strategy to achieve ion screening at the channel source, thereby improving ion channel selectivity.

[0032] In some embodiments, the metal-organic framework particles contain unsaturated metal sites that anchor lithium salt anions to increase the lithium ion transference number.

[0033] "Unsaturated metal sites": refers to unsaturated metal centers in the inner wall of the pores of metal-organic framework particles. Each metal center has at least one empty coordination site, which is used to form a coordination bond with lithium salt anions and generate an anchoring effect.

[0034] Metal-organic framework particles contain unsaturated metal sites, which anchor lithium salt anions. This anchoring effect restricts anion movement, thereby increasing the lithium-ion transference number. Increased lithium-ion transference number reduces concentration polarization, thus enhancing the ion transport capability of continuous ion channels. This, in turn, synergizes with continuous electron channels to achieve "how to simultaneously construct continuously isolated ion-electron dual transport channels within a solid-state cathode." The embodiments of this application utilize intrinsic metal sites in the framework to achieve anion immobilization, improving ion channel selectivity without the need for additional additives.

[0035] In some embodiments, the surface of the metal-organic framework particles has -OH or -COOH functional groups, which are covalently grafted onto the conductive polymer layer.

[0036] "-OH or -COOH functional groups": These refer to hydroxyl or carboxyl groups that are directly connected to the organic ligands of metal-organic framework particles in the form of covalent bonds, and are used to form covalent grafting points with conductive polymer layers.

[0037] The metal-organic framework (MOF) particles have -OH or -COOH functional groups on their surface, which are covalently grafted onto the conductive polymer layer. This covalent grafting enhances the interfacial bonding strength between the conductive polymer layer and the MOF particles. Increased interfacial bonding strength reduces interfacial resistance, thereby strengthening the electron transport stability of the continuous electron channel. This, together with the continuous ion channel, enables the simultaneous construction of a continuously isolated ion-electron dual transport channel within a solid cathode. In this embodiment, the electron channel is fixed by chemical bonding, preventing the conductive polymer layer from peeling off and failing during cycling.

[0038] In some embodiments, the lithium salt electrolyte is selected from at least one of LiPF6, LiTFSI, LiDFP, LiDFOB, LiTFS, LiBF4, Li3PS4, Li6PS5X or Li2S, wherein X is Cl, Br or I.

[0039] The lithium salt electrolyte is selected from at least one of LiPF6, LiTFSI, LiDFP, LiDFOB, LiTFS, LiBF4, Li3PS4, Li6PS5X, or Li2S, thereby providing a lithium-ion source that can fill a regular one-dimensional channel. The lithium-ion source forms a continuous ion channel within the regular one-dimensional channel, thus providing a continuous lithium-ion transport path for the positive electrode active material. This, together with the continuous electron channel, achieves "how to simultaneously construct a continuously isolated ion-electron dual transport channel within a solid-state positive electrode." The embodiments of this application cover various types of inorganic, organic, and sulfide lithium salts, meeting the requirements for compatibility with different electrochemical windows and interfaces.

[0040] In some embodiments, the lithium salt electrolyte is present in a high-concentration loading manner within the one-dimensional channel to create a locally high ionic conductivity environment within the one-dimensional channel.

[0041] "High concentration loading method" refers to the filling amount of lithium salt electrolyte in a regular one-dimensional channel reaching more than 70% of the channel volume, in order to form a local high ionic conductivity environment.

[0042] The lithium salt electrolyte exists in a high-concentration loading mode within a regular one-dimensional channel, thereby creating a locally high ionic conductivity environment within the channel. This locally high ionic conductivity environment shortens ion transport time; shortened ion transport time reduces polarization, thus enhancing the ion transport capability of the continuous ion channel. This, together with the continuous electron channel, achieves the goal of "simultaneously constructing a continuously isolated ion-electron dual transport channel within a solid-state cathode." The embodiments of this application utilize the confined space of the channel to achieve the stable existence of a high-concentration lithium salt, thereby improving the intrinsic conductivity of the ion channel.

[0043] In some embodiments, the conductive polymer layer is at least one of PEDOT-b-PEO block copolymer, self-doped polyaniline derivative SPAN, or PEDOT derivative containing sulfonic acid groups.

[0044] "Self-doped polyaniline derivative SPAN": refers to an intrinsically conductive polymer whose main chain is composed of aniline units and whose side chains have sulfonic acid groups, which can provide electronic conductivity without the addition of external dopants.

[0045] The conductive polymer layer is at least one of PEDOT-b-PEO block copolymer, self-doped polyaniline derivative SPAN, or PEDOT derivative containing sulfonic acid groups, thereby providing an electronically conductive framework. This framework forms continuous electron channels on the outer surface of the metal-organic framework particles, providing a continuous electron transport path for the positive electrode active material. This, together with the continuous ion channels, achieves the goal of "simultaneously constructing continuous and isolated ion-electron dual transport channels within a solid-state positive electrode." The embodiments of this application employ a self-doped or block structure design to avoid the loss of small molecule dopants and improve the long-term stability of the electron channels.

[0046] In some embodiments, single-walled carbon nanotubes are synchronously composited within the conductive polymer layer, and the single-walled carbon nanotubes form a three-dimensional conductive network within the conductive polymer layer.

[0047] "Single-walled carbon nanotubes" refer to one-dimensional carbon materials with diameters of 1–100 nm and lengths of 1–10 μm, formed by rolling up a single layer of graphene, used to form a three-dimensional conductive network within a conductive polymer layer.

[0048] Single-walled carbon nanotubes are synchronously composited within the conductive polymer layer, forming a three-dimensional conductive network. This three-dimensional conductive network enhances the conductivity of the continuous electron channels. Increased conductivity reduces electron transport resistance, thereby strengthening the electron transport capability of the continuous electron channels. This, together with continuous ion channels, achieves the goal of "simultaneously constructing continuously isolated ion-electron dual transport channels within a solid-state cathode." In this embodiment, a one-dimensional highly conductive nanomaterial is introduced to construct a cross-particle electron bridge, further reducing the electron channel resistance.

[0049] In some embodiments, the thickness of the conductive polymer layer is ultrathin, which is formed directly by in-situ oxidative polymerization, and the specific value range of the ultrathin layer is 2 nm to 500 nm.

[0050] The conductive polymer layer has an ultrathin thickness, formed directly through in-situ oxidative polymerization. This ultrathin thickness reduces the tortuosity of the ion transport path, thereby lowering ion transport resistance and preventing excessive blockage of continuous ion channels. This, combined with continuous electron channels, enables the simultaneous construction of continuously isolated ion-electron dual transport channels within a solid-state cathode. This application's embodiments directly generate nanoscale thicknesses through in-situ oxidative polymerization, balancing electron coverage and ion accessibility. Ultrathin thicknesses include, but are not limited to, 2nm, 5nm, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm, and 500nm.

[0051] In some embodiments, the positive electrode active material is NCM811.

[0052] The positive electrode active material is NCM811, which provides reversible lithium insertion / extraction active sites. These active sites simultaneously contact continuous ion channels and continuous electron channels, thereby enabling the synchronous insertion and extraction of lithium ions and electrons, and thus realizing "how to simultaneously construct continuously isolated ion-electron dual transport channels within a solid-state positive electrode". In this application embodiment, a high-nickel layered oxide is coupled with a dual continuous channel structure to fully leverage the advantages of high capacity and high speed.

[0053] In some embodiments, the composite material has a positive electrode area loading ≥4 mAh / cm². 2 At the same rate, the capacity retention is ≥90% at 1C and ≥80% at 2C. The electronic conductivity of the composite material decreases by less than 10% after 500 cycles.

[0054] The ion-electron dual-continuous conductor cathode composite material exhibits a capacity retention of ≥90% at 1C rate and ≥80% at 2C rate when the cathode unit area loading is ≥4mAh / cm². After 500 cycles, the electronic conductivity of the ion-electron dual-continuous conductor cathode composite material decays by <10%. This simultaneously meets the requirements of high loading capacity, high rate capability, and long lifespan, thus verifying that the problem of "how to simultaneously construct a continuous and isolated ion-electron dual transport channel within a solid-state cathode" has been solved. The embodiments of this application simultaneously improve loading capacity, rate capability, and cycle stability through a dual-continuous structure, overcoming the bottleneck of traditional solid-state cathodes that cannot simultaneously achieve all three.

[0055] The positive electrode's load capacity per unit area includes, but is not limited to, 4 mAh / cm². 2 4.5mAh / cm 2 5mAh / cm 2 5.5mAh / cm 2 6mAh / cm 2 Etc.; Capacity retention at 1C rate includes, but is not limited to, 90%, 91%, 92%, 93%, 94%, 95%; Capacity retention at 2C rate includes, but is not limited to, 80%, 81%, 82%, 83%, 84%, 85%; Electronic conductivity decay rate includes, but is not limited to, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%.

[0056] In summary, the mechanism of the ion-electron dual continuous conductor positive electrode composite material provided in this application includes: 1. Electro-mechanical coupling stability mechanism of the pore-polymer "spatial interlocking" interface Geometric Interlocking: MOF-Ruled One-Dimensional Channels <110> The zone axis is arranged in a hexagonal or tetragonal periodic pattern, and the aperture and wall form a "rigid grid." The conductive polymer layer thickness is 2–50 nm, which is just at the critical scale between electron tunneling and ohmic conduction. When the polymer thickness is <2 nm, the carrier tunneling barrier increases, and the electronic conductivity drops sharply; when it is >50 nm, the polymer has more π-π stacking defects, the Young's modulus decreases, and buckling and peeling are prone to occur during cycling. Therefore, 2–50 nm is the "geometric interlocking window" with the optimal mechanical-electrical synergy of electron channels.

[0057] Chemical interlocking: -OH / -COOH forms covalent ester or ether bonds with the polymer chain ends, with bond energies >350 kJ / mol. -1 It is much higher than van der Waals adhesion (~50 kJmol). -1 Under the repeated volume expansion of 500 cycles (the c-axis of the NCM811 lattice changes by ~2.6%), covalent anchoring can transfer shear stress from the polymer layer to the rigid MOF framework, increasing the critical stress of interface slip by >5 times, thereby suppressing cracking of the conductive layer and reducing electronic conductivity by <10%.

[0058] Charge interlocking: The coordination constant logK of the unsaturated metal site to TFSI- is greater than 4, and the Li+ transport number t+ in the channel increases from 0.25 to 0.78. When the polymer on the outer surface generates a trace electron depletion layer due to redox reaction, the high t+ in the channel can shield the space charge layer from repulsion of Li+, avoiding the increase of the interface barrier induced by "ion-electron double depletion", thereby maintaining the dual-channel cooperative transport.

[0059] 2. Confined conduction model of high-concentration lithium salt in a "quasi-liquid" state Phase state under solvent-deficient environment: when the pore size is slightly larger than that of desolvated Li + At 3.4 Å, LiTFSI exists in the pores as an "ion pair-ion cluster"; the polar functional groups (-OH, -COOH, unsaturated metal sites) on the pore walls provide a local "quasi-solvation sheath," allowing Li+ to diffuse continuously in a "jump-glide" manner along the mean square displacement of the pore axis, with an effective diffusion coefficient D‖ reaching 10. -10 m 2 s -1 Approaching the level of liquid electrolyte (10 -10 m 2 s -1 ).

[0060] Critical phenomenon at the concentration window: When the lithium salt filling rate is >70%, a "continuous ion cluster network" forms within the pores, and the conductivity increases sharply with the filling rate in a percolation-like manner; when it is <70%, the ion clusters are isolated, and the conductivity decreases by two orders of magnitude. This percolation threshold matches the theoretical prediction of 67% for "directional flow" in one-dimensional pore geometry, confirming that a high concentration loading is a necessary condition for obtaining continuous ion channels.

[0061] Thermo-mechanical stability: The lithium salt lattice distortion energy ΔEconf > 50 meV within the confined space suppresses lattice rearrangement at high temperatures, allowing the composite particles to remain crystallization-free at 120°C. In contrast, macroscopic solid electrolyte films exhibit grain boundary crystallization at 90°C, leading to ion blockage. Thus, pore confinement not only improves ionic conductivity at room temperature but also maintains channel continuity under thermal abuse.

[0062] 3. Conductive polymer-carbon nanotube "dual continuous flow" electronic framework Dimensional complementarity: PEDOT segments are one-dimensional π-conjugated, while SWCNTs are zero-dimensional to one-dimensional transition structures; when the volume fraction of SWCNTs > 0.6%, the system exhibits "bicontinuous percolation," meaning that the polymer chains and carbon nanotube network simultaneously cross the particle surface to form a three-dimensional conductive framework, with electronic conductivity increasing from 10⁻² Scm. -1 Jump to 10 Scm -1 .

[0063] Interface barrier modulation: The work function of SWCNT is ~5.1 eV, which differs from the HOMO level of PEDOT (-5.2 eV) by only 0.1 eV, forming an ohmic contact; the electron transfer resistance from CNT to polymer chain is <5 Ωcm. 2 Far lower than polymer-active material point contact (>100Ωcm) 2 This shifts the electron transport bottleneck from the "particle-particle" interface to the "particle-active material" interface, reducing overall polarization.

[0064] Mechanical buffer: SWCNT has a flexural modulus of ~1TPa and forms a "nanospring" within the polymer layer. It can absorb the radial stress (~200MPa) generated by the volume expansion of NCM811, reduce the crack density of the polymer layer by 60%, and further ensure the integrity of the electron channel after 500 cycles.

[0065] 4. The positive electrode active material and the dual-channel "point-surface-volume" three-level contact Point contact: The spinel phase (NiO-like) on the surface of NCM811 secondary particles forms Li with the sulfonic acid groups of the conductive polymer layer. + -SO3- electrostatic adsorption reduces contact resistance.

[0066] Surface contact: The NCM811 primary particle (100) crystal plane has a lattice mismatch of <5% with the MOF channel opening. The Li+ escaping from the channel can be directly embedded into the NCM811 surface lattice, shortening the ion diffusion length to <50nm.

[0067] Bulk contact: Under high loading (≥4mAhcm-2), the electrode thickness is ~80μm. The ion diffusion path of traditional electrodes is too long (>40μm), which leads to a decrease in capacity utilization. In this solution, the MOF channel forms an "ion highway" in the electrode thickness direction, and the theoretical diffusion path is shortened to the channel length (~5μm), which improves the capacity utilization by >15%.

[0068] 5. The "self-healing" mechanism of cycle life Electron channel self-healing: Sulfonic acid groups doped within the conductive polymer layer can react with Li in the oxidized state. + Reversible ionic crosslinking is formed; when the polymer chain breaks due to mechanical fatigue, the fracture interface passes through Li + -SO3 rebridging allows electronic conductivity to recover to >90% after standing for 12 hours.

[0069] Ion channel self-healing: Unsaturated metal sites on the inner wall of MOF channels can capture dissolved transition metal ions (Ni) during cycling. 2+ Co 2+This prevents the ions from migrating to the solid electrolyte side and causing interfacial side reactions. After capture, the pore size is reduced by <0.2Å, but is still larger than desolvated Li+, so the ion flux is not hindered, and the source of side reactions is "self-purified", thereby extending the cycle life of the full cell.

[0070] 6. Solvent-binder synergistic strategy for industrial roll-to-roll coating Solvent selection: Acetonitrile, boiling point 82°C, surface tension ~29 mNm -1 Lower than N-methylpyrrolidone (NMP, ~40mNm) -1 The spreading coefficient on aluminum foil is >0, enabling complete evaporation within 3 minutes under hot air drying conditions at ≤100°C, and meeting the requirement of a roll-to-roll speed ≥1 mm / min. -1 .

[0071] Adhesive migration: PVDF has a solubility of only ~1wt% in acetonitrile. During the drying process, PVDF segments migrate to the aluminum foil interface, forming a "bottom adhesive layer," while MOF-conductive polymer composite particles are enriched on the electrode surface, ensuring both adhesion strength (peel force >10Nm) and adhesion strength. -1 This also exposes the dual continuous channels to the electrolyte side, reducing the interfacial impedance.

[0072] Thickness window: When the electrode thickness is >120μm, drying stress causes cracks; by introducing 5wt% PEO-b-PMMA block copolymer as a toughening agent, the fracture strain can be increased from 1.8% to 4.2%, realizing an ultra-high load capacity crack-free electrode of ≥6mAhcm-2, providing a process basis for the next generation of high-energy solid-state batteries.

[0073] Therefore, this application achieves dual continuity and mutual isolation of ions and electrons within a single composite particle through a spatial partitioning strategy of "MOF channel-confined ion channels + ultrathin conductive polymer electron channels on the surface." By leveraging geometric, chemical, and charge triple interlocking, it resolves the core contradiction of "discontinuous ion-electron transport" in high-load, high-rate, and long-life solid-state cathodes. This integrated structure-process design can be directly embedded into existing roll-to-roll production lines, paving the way for all-solid-state batteries to reach >400Wh / kg capacity. -1 A cycle of >1000 cycles provides a scalable technology path.

[0074] Secondly, embodiments of this application provide a solid positive electrode comprising the ion-electron dual continuous conductor positive electrode composite material, a conductive agent, and a binder as described in any of the first aspects.

[0075] The solid-state positive electrode comprises an ion-electron dual-continuous conductor positive electrode composite material, a conductive agent, and a binder. The ion-electron dual-continuous conductor positive electrode composite material provides continuous ion channels and continuous electron channels; the conductive agent supplements external electron conduction between particles; and the binder fixes the mechanical connections between particles. The three work together to form a complete solid-state positive electrode. The embodiments of this application retain the advantages of the dual-continuous structure at the electrode level, while improving the external electronic and mechanical network through the conductive agent and binder.

[0076] Thirdly, embodiments of this application provide an all-solid-state lithium battery, including the solid positive electrode, solid electrolyte, and negative electrode described in the second aspect.

[0077] The all-solid-state lithium battery comprises a solid positive electrode, a solid electrolyte, and a negative electrode. A continuous ion channel and a continuous electron channel are simultaneously established within the solid positive electrode. The solid electrolyte provides ion connectivity between the negative electrode and the solid positive electrode. The negative electrode provides an electronic circuit; the three components form a closed battery system. This application's embodiment is the first to couple a dual continuous positive electrode with a sulfide solid electrolyte, achieving high-rate operation of the entire battery.

[0078] In some embodiments, the solid electrolyte is a sulfide fast ion conductor xLi2S-(1-x)P2S5, where x = 0.6-0.8.

[0079] The solid electrolyte is a sulfide fast ion conductor xLi₂S⁻(1-x)P₂S₅ with x = 0.6-0.8, thus providing high ionic conductivity. High ionic conductivity reduces ion transport resistance at the interface between the solid electrolyte and the solid cathode. Reduced resistance decreases interfacial polarization, which, in turn, works synergistically with the continuous ion channels within the solid cathode to achieve "how to simultaneously construct continuous and isolated ion-electron dual transport channels within the solid cathode." In this application, a high-conductivity sulfide electrolyte is selected to match the dual continuous cathode, eliminating the interfacial ion bottleneck and achieving high power output of the full cell. x includes, but is not limited to, 0.6, 0.65, 0.7, 0.75, 0.8, etc.

[0080] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to industry standards. If there is no corresponding industry standard, then generally accepted international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0081]

Example 1

[0082]

Example 2

[0083]

Example 3

[0084]

Example 4

[0085]

Example 5

[0086]

Example 6

[0087]

Example 7

[0088]

Example 8

[0089]

Example 9

[0090] Comparative Example 1 Comparative Example 1 does not use an ion-electron dual continuous conductor positive electrode composite material, but only uses traditional conductive carbon black as a conductive agent. The remaining steps are the same as in Example 1: Step D1.1 Weigh NCM811 positive electrode active material, carbon black conductive agent, and PVDF binder and mechanically mix them in a mass ratio of 80:10:5:5. Coat the mixture onto aluminum foil and dry it to obtain a solid positive electrode. Step D1.2 Using the solid positive electrode obtained in step D1.1 as the working electrode, lithium metal as the counter electrode, and sulfide solid electrolyte xLi2S-(1-x)P2S5 (x=0.7) as the solid electrolyte, assemble an all-solid-state lithium battery.

[0091] Experimental methods for evaluating results: Cathode unit area loading determination: The solid cathode was punched into 12mm diameter discs, the mass of the discs was weighed and the mass of the active material was calculated, based on the theoretical specific capacity of NCM811 of 275mAh·g. -1 Convert and record the capacity per unit area.

[0092] Capacity retention rate determination: Under constant current conditions of 25℃ and 1C, the all-solid-state lithium battery was subjected to constant current charge-discharge cycles. The discharge capacity of the first cycle was recorded as C0, and the discharge capacity of the 100th cycle was recorded as C1. Capacity retention rate = C1 / C0 × 100%.

[0093] Table 1. Effect data of each embodiment and comparative example.

[0094] As shown in Table 1, the technological advancements of this application's technical solution compared to the comparative example include: 1. Significantly improved cathode capacity per unit area: The capacity range of Examples 1-9 reaches 4.1–6.2 mAh·cm⁻¹. -2 Compared to Comparative Example 1, which has a capacity of 2.9 mAh·cm⁻¹ -2 Improvements of 41%–114%. Example 9, for the first time, achieved over 6 mAh·cm⁻¹ in a solid-state cathode. -2 Ultra-high load capacity (6.2 mAh·cm³) -2 While maintaining a capacity retention rate of 90.1%, it breaks through the traditional limitation of solid-state battery electrode loading of 3 mAh·cm³. -2 The following technical bottlenecks make the commercialization of high-energy-density batteries feasible.

[0095] 2. Significantly improved high-rate cycling performance: At 1C, the capacity retention of Examples 1-9 is ≥90.1%, an improvement of 9.2–13.3 percentage points compared to 80.9% in Comparative Example 1. This demonstrates that the dual-continuous channel structure effectively reduces charge transfer impedance and concentration polarization.

[0096] 3. Synergistic improvement of high capacity and high rate performance: Traditional technologies often face the constraint that "increased capacity leads to decreased rate performance," while this application achieves simultaneous optimization of rate performance while increasing capacity. Specifically, Example 6 achieves this at 5.2 mAh·cm⁻¹. -2 Even under high loading, it still maintains a 93.5% 1C retention rate. Example 5 at 4.8 mAh·cm⁻¹ -2 The highest retention rate of 94.2% was achieved under load, verifying the effectiveness of the ion-electron dual continuous conductor structure in solving solid-solid interface problems.

[0097] 4. Verification of the universality of the dual continuous channel structure: Examples using different MOF supports (ZIF-8, MIL-101(Cr), UiO-66 series, Mg-MOF-74, Ni-MOF-74) and different conductive polymers (PEDOT-b-PEO, SPAN, PEDOT derivatives containing sulfonic acid groups) all showed better electrochemical performance than the comparative examples, proving that the spatial partitioning strategy of "pore-confined ion channels + ultrathin surface electron channels" has good material adaptability and technical scalability.

[0098] In summary, this application embodiment achieves ≥4 mAh·cm³ ion-electron dual transport channels simultaneously in a solid-state cathode for the first time by constructing spatially isolated and continuously connected ion-electron dual transport channels. -2 The high loading capacity and ≥90% high rate capacity retention rate solve the core problems in existing technologies, such as discontinuous ion-electron transport paths, large interface polarization, and short cycle life caused by poor solid-solid contact. This paves the way for all-solid-state lithium batteries to reach >400 Wh·kg capacity. -1 The energy density target provides a key cathode structure solution.

[0099] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A composite material for an ion-electron dual continuous conductor, characterized in that, include: Metal-organic framework particles with regular one-dimensional channels; A lithium salt electrolyte pre-filled within the one-dimensional channel, wherein the lithium salt electrolyte forms a continuous ion channel within the one-dimensional channel; A conductive polymer layer in situ polymerized on the outer surface of the metal-organic framework particles, the conductive polymer layer forming continuous electron channels on the outer surface of the metal-organic framework particles; and Positive electrode active material mechanically mixed with the metal-organic framework particles; The continuous ion channel and the continuous electron channel are spatially isolated from each other and are continuous, so as to provide both ion transport path and electron transport path in the solid cathode.

2. The composite material according to claim 1, characterized in that, The metal-organic framework is at least one of ZIF-8, MIL-101(Cr), UiO-66-(OH)2, UiO-66-(COOH)2, Mg-MOF-74 or Ni-MOF-74.

3. The composite material according to claim 1 or 2, characterized in that, The pore size of the metal-organic framework particles is slightly larger than that of desolvated Li. + Diameter, to achieve desolvation of Li + Size-selective transmission.

4. The composite material according to claim 1 or 2, characterized in that, The metal-organic framework particles contain unsaturated metal sites, which anchor lithium salt anions to increase the lithium ion transference number.

5. The composite material according to claim 1 or 2, characterized in that, The surface of the metal-organic framework particles has -OH or -COOH functional groups, which are covalently grafted onto the conductive polymer layer.

6. The composite material according to claim 1, characterized in that, The lithium salt electrolyte is selected from at least one of LiPF6, LiTFSI, LiDFP, LiDFOB, LiTFS, LiBF4, Li3PS4, Li6PS5X or Li2S, wherein X is Cl, Br or I.

7. The composite material according to claim 1 or 6, characterized in that, The lithium salt electrolyte exists in the one-dimensional channel in a high-concentration loading manner to form a local high ionic conductivity environment in the one-dimensional channel.

8. The composite material according to claim 1, characterized in that, The conductive polymer layer is at least one of PEDOT-b-PEO block copolymer, self-doped polyaniline derivative SPAN, or PEDOT derivative containing sulfonic acid groups.

9. The composite material according to claim 1 or 8, characterized in that, Single-walled carbon nanotubes are synchronously composited within the conductive polymer layer, forming a three-dimensional conductive network within the conductive polymer layer.

10. The composite material according to claim 1 or 8, characterized in that, The thickness of the conductive polymer layer is ultrathin, and the ultrathin layer is formed directly by in-situ oxidative polymerization. The specific numerical range of the ultrathin layer is 2 nm to 500 nm.

11. The composite material according to claim 1, characterized in that, The positive electrode active material is NCM811.

12. The composite material according to claim 1, characterized in that, The composite material has a positive electrode unit area loading capacity ≥4mAh / cm². 2 At the same rate, the capacity retention is ≥90% at 1C and ≥80% at 2C. The electronic conductivity of the composite material decreases by less than 10% after 500 cycles.

13. A solid-state positive electrode, characterized in that, It includes the ion-electron dual continuous conductor positive electrode composite material, conductive agent, and binder as described in any one of claims 1 to 12.

14. An all-solid-state lithium battery, characterized in that, It includes the solid positive electrode, solid electrolyte, and negative electrode as described in claim 13.

15. The all-solid-state lithium battery according to claim 14, characterized in that, The solid electrolyte is a sulfide fast ion conductor xLi2S-(1-x)P2S5, where x = 0.6-0.8.

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