Alkali-metal-ion conducting organic redox materials and rechargeable solid-state batteries made thereof

Abstract

The present disclosure pertains to redox molecules with structures described herein. The present disclosure also pertains to an electrode that includes the molecules. The electrode may include a cathode. The present disclosure also pertains to an electrochemical cell with a cathode that includes a molecule of the present disclosure. The electrochemical cell may include a solid-state battery that includes: a cathode with a molecule of the present disclosure, an anode, and a solid electrolyte between the cathode and the anode.

Description

TITLEALKALI-METAL-ION CONDUCTING ORGANIC REDOX MATERIALS AND RECHARGEABLE SOLID-STATE BATTERIES MADE THEREOFCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 659,654, filed on June 13, 2024. The entirety of the aforementioned application is incorporated herein by reference.BACKGROUND

[0002] A need exists for cathodes with enhanced electrochemical performance. Numerous embodiments of the present disclosure aim to address the aforementioned need.SUMMARY

[0003] In some embodiments, the present disclosure pertains to a molecule that includes, without limitation:a derivative thereof, a tautomer thereof, an oligomer thereof, or combinations thereof.

[0004] In some embodiments, M is a metal. In some embodiments, M is an alkali metal, such as Li, Na, K, or combinations thereof. In some embodiments, the molecule is alkali-metal ion conductive.

[0005] Additional embodiments of the present disclosure pertain to an electrode that includes a molecule of the present disclosure. In some embodiments, the electrode includes a cathode.

[0006] In some embodiments, the electrode is a component of an electrochemical cell. Additional embodiments of the present disclosure pertain to an electrochemical cell with a cathode that includes a molecule of the present disclosure. In some embodiments, the electrochemical cell includes a solid-state battery. In some embodiments, the solid-state battery includes: a cathode that includes a molecule of the present disclosure, an anode, and a solid electrolyte between the cathode and the anode.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 shows quinone-based molecular structures and synthetic procedures for Li2-TAQ and Li4-TAQ. TAQ is the acronym of bis-tetraaminobenzoquinone. Corresponding theoretical capacity is shown.

[0008] FIG. 2 shows the reversible electrochemical reactions of a quinone-based molecule where the electrochemical process can start either from the oxidized form (TAQ) or the reduced form (M4-TAQ) or the intermediate form (M2-TAQ). M can be Li or Na or K.

[0009] FIG. 3 shows attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectra of TAQ, Li2-TAQ and Li4-TAQ.

[0010] FIG. 4 shows the7Li (nuclear magnetic resonance) NMR spectra of Li2-TAQ and Li4-TAQ.

[0011] FIGS. 5A-5C show powder x-ray diffraction (PXRD) patterns of TAQ (FIG. 5A), Li2-TAQ (FIG. 5B) and Li4-TAQ (FIG. 5C).

[0012] FIGS. 6A-6C show scanning electron microscopy (SEM) images of TAQ (FIG. 6A), Li2-TAQ (FIG. 6B) and Li4-TAQ (FIG. 6C).

[0013] FIGS. 7A-7C show the first cycle electrochemical performance of TAQ (FIG. 7A), L12-TAQ (FIG. 7B), and Li4-TAQ (FIG. 7C) in liquid electrolyte-based cells.

[0014] FIGS. 8A-8C show normalized electron paramagnetic resonance (EPR) spectra of TAQ (FIG. 8A), Li2-TAQ (FIG. 8B) and Li4-TAQ (FIG. 8C) recorded at 300 K.

[0015] FIGS. 9A-9D show the electron-blocking cell configuration (FIG. 9A), d.c. polarization measurements of Li4-TAQ (FIG. 9B), d.c. polarization measurements of Li2-TAQ (FIG. 9C), and temperature-dependent ionic conductivity (FIG. 9D).

[0016] FIGS. 10A-10D show solid-state battery cell structure and corresponding charge / discharge profiles (FIG. 10A) for TAQ (FIG. 10B), Li2-TAQ (FIG. 10C), and Li4-TAQ (FIG. 10D) using sulfide electrolyte. Black dots represent the status of the cell at open circuit.

[0017] FIGS. 11A-11B show impact of cathode fraction on the utilization (FIG. 11A) and electrodelevel specific energy (FIG. 11B) of TAQ, Li2-TAQ, and Li4-TAQ at 0.1C.

[0018] FIGS. 12A-12B show FTIR spectra of pristine TAQ, Li2-TAQ, U4-TAQ and the corresponding mixture with sulfide electrolyte (FIG. 12A) and distribution of relaxation time (DRT) plots for fresh cells using TAQ and Li4-TAQ electrodes with a 70 wt.% cathode fraction (FIG. 12B).

[0019] FIGS. 13A-13D show rate capability of organic solid-state batteries with 40-70 wt.% cathode fractions for TAQ (FIG. 13A) and IJ4-TAQ (FIG. 13B). Corresponding discharge capacity retention for TAQ (FIG. 13C) and Li4-TAQ (FIG. 13D) at 0.1C, 0.2C, 0.33C and 0.5C.

[0020] FIGS. 14A-14D show cycling stability of solid-state cells cycled at 0.5C including TAQ, Li2- TAQ, and IJ4-TAQ with 40 wt.% cathode fraction and 4 mg / cnr cathode loading (FIG. 14A), Li4- TAQ (FIG. 14B), TAQ with different cathode fractions and 4 mg / cnr cathode loading (FIG. 14C), and Li4-TAQ and TAQ with 60 wt.% and 40 wt.% cathode fraction and 20 mg / cm2and 12 mg / cnr cathode loading, respectively (FIG. 14D).

[0021] FIGS. 15A-15D show a solid-state battery cell structure (FIG. 15A) and corresponding charge / discharge profiles (FIGS. 15B-15D) for TAQ (FIG. 15A), Lii-TAQ (FIG. 15B), and Li4-TAQ (FIG. 15C) using halide electrolyte. Black dots represent the status of the cell at open circuit.

[0022] FIGS. 16A-16C show first-cycle galvanostatic charge / discharge curves (FIG. 16A), rate capability (FIG. 16B) and cycling stability over 150 cycles (FIG. 16C) for solid-state cells using TAQ as the cathode active materials cycled at 0.5 C under different stack pressures.

[0023] FIGS. 17A-17B show first-cycle galvanostatic charge / discharge profile of solid-state cells using TAQ as the cathode active materials (FIG. 17A) and corresponding cross-sectional SEM images of the electrode taken at different states of charge (FIG. 17B).

[0024] FIGS. 18A-18C show snapshots from the operando SEM images of three individual TAQ particles (FIG. 18A), analysis tracking particle size changes during cycling (FIG. 18B) and TAQ particle size evolution at various states of charge (FIG. 18C).DETAILED DESCRIPTION

[0025] It is to be understood that both the foregoing general description and the following detailed description are illustrative and explanatory, and are not restrictive of the subject matter, as claimed. In this application, the use of the singular includes the plural, the word “a” or “an” means “at least one”, and the use of “or” means “and / or”, unless specifically stated otherwise. Furthermore, the use of the term “including”, as well as other forms, such as “includes” and “included”, is not limiting.Also, terms such as “element” or “component” encompass both elements or components that includes one unit and elements or components that include more than one unit unless specifically stated otherwise.

[0026] The section headings used herein are for organizational purposes and are not to be construed as limiting the subject matter described. All documents, or portions of documents, cited in this application, including, but not limited to, patents, patent applications, articles, books, and treatises, are hereby expressly incorporated herein by reference in their entirety for any purpose. In the event that one or more of the incorporated literature and similar materials defines a term in a manner that contradicts the definition of that term in this application, this application controls.

[0027] Solid-state batteries (SSBs) based on metal anodes are foreseen to be a major advancement in energy storage technology, promising higher energy densities, enhanced safety, and wide operating temperature windows. Inorganic cathodes, such as lithium nickel manganese cobalt oxides (NMC), are considered as the preferred cathode for SSB applications due to their high energy metrics, high electronic and ionic conductivities, and robust structural stability. However, NMC cathodes face mechanical and chemical incompatibility with solid-state electrolytes (SSEs), which limits their performance and leads to cell failure. Additionally, cobalt and nickel present significant supply chain challenges due to its scarcity and geopolitical limitations.

[0028] Recently, organic electrode materials (OEMs) have emerged as sustainable redox active materials showcasing promising electrochemical performances in various energy storage systems. The potential synergy between SSEs and OEMs holds promise for enabling energy dense SSBs with high safety, low cost, and long-term stability. Owing to their malleability, OEMs are recognized for their ability to maintain conformal interfaces with ceramic electrolytes, thus addressing some of the chemomechanical deficiencies observed in their inorganic counterparts.

[0029] A handful OEMs have been reported to store Li+and Na+in solid-state cells with promising electrochemical performances (Ref. 1). For instance, pyrene-4,5,9,10-tetraone (PTO) exhibits high specific capacity of 400 mAh / g and extended cycling stabilities, reaching 500 cycles without any significant capacity fade (Refs. 2-3). However, despite these achievements, PTO suffers from both low ionic and electronic conductivities, limiting its rate performance and weight fraction in the cathode composite.

[0030] Additionally, many OEMs have been explored as active materials for energy storage in solid- state cell configuration. However, their poor electronic and ionic conductivity limit their weight fraction in the electrode composite. For instance, Chen ct al. reported a fused quinone molecule, bis- tetraaminobenzoquinone (TAQ), with an electrical conductivity on the order of 10-4S / cm, demonstrating excellent performance at high cathode fractions (e.g. >90 wt.%) in liquid electrolytebased cell configuration (Refs. 4-6). However, no solid-state batteries based on TAQ have been reported. In solid-state cell configuration, both electrical and ionic conductivities are crucial for maintaining high material utilization at high cathode fractions.

[0031] As such, a need exists to resolve the sustainability challenges associated with cathodes in SSBs. Recently, many OEMs have emerged as cost-effective and sustainable alternative active materials for energy storage in all-solid-state batteries. Thanks to their malleability and multi-electron redox reaction, most OEMs exhibit high specific capacities along with extended cyclability. However, these electrochemical performances are typically achieved at low cathode fractions (e.g., <40 wt.%), resulting in low cell-level energy metrics. For practical applications, OEMs must also possess high bulk electronic and ionic conductivity in addition to these advantages. Numerous embodiments of the present disclosure aim to address the aforementioned need.

[0032] Molecules

[0033] In some embodiments, the present disclosure pertains to a redox molecule. In some embodiments, the molecule includes, without limitation:, a derivative thereof, a tautomer thereof, an oligomer thereof, or combinations thereof.

[0034] In some embodiments, M is a metal. In some embodiments, M is an alkali metal. In some embodiments, M is an alkali metal that includes, without limitation, Li, Na, K, or combinations thereof. In some embodiments, the molecule is alkali-metal ion conductive.

[0035] Electrodes

[0036] Additional embodiments of the present disclosure pertain to an electrode that includes a molecule of the present disclosure. In some embodiments, the electrode includes an anode. In some embodiments, the electrode includes a cathode.

[0037] The electrodes of the present disclosure may include various amounts of molecules. For instance, in some embodiments, the molecules constitute at least 40 wt.% of the electrode. In some embodiments, the molecules constitute at least 60 wt.% of the electrode. In some embodiments, the molecules constitute between 40 wt.% and 70 wt.% of the electrode.

[0038] In some embodiments, the electrode is a component of an electrochemical cell, such as the electrochemical cells described herein. For instance, in some embodiments, the electrochemical cell is a solid-state battery.

[0039] Electrochemical cells

[0040] Additional embodiments of the present disclosure pertain to an electrochemical cell that includes one or more molecules of the present disclosure. In some embodiments, the electrochemical cells of the present disclosure include a cathode that includes one or more molecules of the present disclosure. In some embodiments, the electrochemical cells of the present disclosure include a solid electrolyte that includes one or more molecules of the present disclosure. In some embodiments, the molecules of the present disclosure are embedded in the solid electrolyte. In some embodiments, the molecules of the present disclosure are embedded in the cathode.

[0041] In some embodiments, the electrochemical cell includes a solid-state battery. In some embodiments, the solid-state battery includes, without limitation, an all-solid-state battery (ASSB), an all-solid-state lithium metal battery (ASSLMBs), all-solid-state lithium secondary battery, an anode- free solid-state battery, or combinations thereof. In some embodiments, the solid-state battery includes: a cathode that includes a molecule of the present disclosure, an anode, and a solid electrolyte between the cathode and the anode.

[0042] The electrochemical cells and solid-state batteries of the present disclosure may include various types of solid electrolytes. For instance, in some embodiments, the solid electrolyte is a sulfide or halide-based solid electrolyte. In some embodiments, the solid electrolyte includes a sulfide electrolyte.

[0043] In some embodiments, the solid electrolyte is a catholyte that includes at least one inorganic compound that is ion-conducting. In some embodiments, the inorganic compound has a formula of AxByCz. In some embodiments, A includes, without limitation, Li, Na, K or combinations thereof. In some embodiments, B includes, without limitation, B, N, P, Si, As, Sc, Y, In, Zr, or combinations thereof. In some embodiments, C includes, without limitation, O, S, Se, F, Cl, Br, I or combinations thereof. In some embodiments, the electrochemical cells and solid-state batteries of the present disclosure also include an electrolyte layer that is entirely inorganic. In some embodiments, the electrochemical cell further includes an interlayer that includes Ag and carbon.

[0044] In some embodiments, the electrochemical cells and solid-state batteries of the present disclosure also include an anode. In some embodiments, the anode includes a metal-based anode, an alkali metal, an anode-free configuration, or combinations thereof. In some embodiments, the anode includes a lithium-based anode.

[0045] The electrochemical cells and solid-state batteries of the present disclosure can include various cathodes. For instance, in some embodiments, the cathode includes an inorganic cathode. In some embodiments, the cathode includes a transition metal oxide cathode. In some embodiments, the cathode is a lithium-ion cathode. In some embodiments, the cathode is lithium nickel manganese cobalt oxides (NMC) cathode. The cathodes of the present disclosure may include various amounts of molecules. For instance, in some embodiments, the molecules constitute at least 40 wt.% of the cathode. In some embodiments, the molecules constitute at least 60 wt.% of the cathode. In some embodiments, the molecules constitute between 40 wt.% and 70 wt.% of the cathode.

[0046] Additional embodiments

[0047] Reference will now be made to more specific embodiments of the present disclosure and experimental results that provide support for such embodiments. However, Applicant notes that the disclosure below is for illustrative purposes only and is not intended to limit the scope of the claimed subject matter in any way.

[0048] Embodiments of the present disclosure introduce alkali-metal-ion conducting fused quinonebased organic redox molecules (OEMs) with an optimal ionic conductivity, and rechargeable solid- state batteries made thereof. Solid-state batteries made with these OEMs can deliver specific capacities up to 350 mAh / g at an average operating voltage of 2.32 V vs. Li+ / Li and stable cycle life at the cathode fraction as high as 70 wt.%. The solid-state cells that include these organic compoundsdeliver high capacities up to 350 mAh / g with capability of 62.4 % of the capacity at cathode fraction as high as 70 wt.%. The resulting cycling stabilities show 92.3% capacity retention after 120 cycles at 50 wt.% and 83.0% capacity retention after 200 cycles at 60 wt.%.

[0049] Applicant reports in this Example the synthesis and characterization of metal-conductive organic compounds based on fused quinone structures with an N-heterocycle (Lix-TAQ). These materials can be used in solid-state batteries with sulfide or halide-based solid electrolytes, and alkali metal anodes. Rechargeable solid-state batteries made of transition metal-free organic cathodes have great potential to reduce cost and improved safety.

[0050] In this Example, Applicant demonstrates a series of lithium-containing fused quinones as cathode active materials for SSBs (FIGS. 1-2). TAQ can be synthesized from tetraamino-p- benzoquinone (TABQ) following the procedure described by Chen et al (Ref. 6). Li2-TAQ and Li4- TAQ may be produced by a two-step synthesis (FIG. 1). First, a strong reducing reagent, radical lithium naphthalene complex, may be formed by reacting naphthalene with lithium metal in dimethoxyethane, followed by a chemical reduction of carbonyl groups in TAQ to form the corresponding lithiated enolates in Lix-TAQ. Different mole ratio of TAQ and lithium naphthalene result in Li2-TAQ and L14-TAQ. The molecular structures of TAQ, Li2-TAQ, and L14-TAQ are confirmed based on ATR-FTIR spectroscopy (FIG. 3). The IR spectrum of TAQ displayed stretching bands in the range of 3464-3228 cm'1, corresponding to N-H stretches from amine groups, and vibration bands at 1651 and 1620 cm"1, corresponding to carbonyl groups. After chemical lithiation, the IR spectra of both Li2-TAQ and Li4-TAQ showed complete disappearance of carbonyl bands accompanied with a significant decrease in band intensity of N-H stretches.

[0051] The amount of Li in Li2-TAQ, and Li4-TAQ was determined using MAS7Li NMR (FIG. 4). Both compounds reveal a broad Li peak at approximately 5 ppm, with peak intensity for Li4-TAQ significantly higher than that of Li2-TAQ. After normalization of integrated intensities, using LiCl as internal reference, the amount of Li in Li4-TAQ and Li2-TAQ was 4 and 1.85 Li per molecule, respectively. Powder XRD (PXRD) measurements revealed that TAQ, Li2-TAQ, and Li4-TAQ powders are crystalline (FIGS. 5A-5C). The PXRD pattern for TAQ matched the one reported by Chen et al. (Ref. 5), confirming a layered structure with an interlayer distance of approximately 3.16A. This interlayer distance increased to about 3.32 A for Li2-TAQ and 3.50 A for Li4-TAQ, due tointercalation of lithium ions between organic layers. TAQ crystallized into rod-shape, with no apparent change in morphology after the chemical lithiation, as shown in FIGS. 6A-6C.

[0052] Galvanostatic chargc / dischargc cycling was performed to probe the electrochemical properties of Li2-TAQ and Li4-TAQ (FIGS. 7A-7C). Self-standing electrodes that include 60 wt.% of active material were used as cathodes, lithium metal as anode, and LP30 (1 M LiPFe in 1 / 1 wt / wt DMC / EC) as electrolyte. The cell using TAQ showed an open circuit voltage (OCV) of 2.78 V and achieved a specific capacity of 303 mAh / g during discharge, which was fully recovered during the subsequent charge. The OCV for the cell with Li2-TAQ remained unchanged, but it recorded a specific capacity of 148 mAh / g after charging and 332 mAh / g after discharging, suggesting the presence of two lithium ions per TAQ2' molecule. In contrast, the OCV for the cell with Li4-TAQ decreased dramatically to 1.69 V. This cell delivered a specific capacity of 276 mAh / g during the first charge, which was fully recovered after the subsequent discharge, indicating that Li4-TAQ may contain four lithium ions per TAQ4-molecule.

[0053] The EPR spectra exhibited intense isotropic signals for organic radicals in TAQ and its lithiated phases (FIGS. 8A-8C). Both TAQ and Li4-TAQ showed EPR signals with equivalent intensities, whereas Li2-TAQ displayed a signal with much higher intensity due to the presence of extra radicals generated by reduction of two carbonyl redox centers in one TAQ2' molecule. The double integrated area under EPR signal (non-normalized) gave a radical concentration of 1.3%, 23.6%, 1.2%, for TAQ, Li2-TAQ, and Li4-TAQ, respectively.

[0054] The Li-ion conductivities of Li2-TAQ and Li4-TAQ were measured in a five-layer electronblocking cell configuration at variable temperatures ranging from 20 to 80 °C, using d.c. polarization technique (FIGS. 9A-9C). At 20 °C, Li2-TAQ and Li4-TAQ exhibited intrinsic bulk ionic conductivities of 2.5xl0'7S / cm and 1.3xl0'6S / cm, respectively. The temperature dependence of the conductivity of Li2-TAQ and Li4-TAQ followed the Arrhenius relationship (FIG. 9D). Li4-TAQ demonstrated a lower activation energy (0.287 eV) compared to Li2-TAQ (0.389 eV), suggesting that ion transport becomes more efficient as the Li+content increases in the TAQ layered structure.

[0055] The solid-state electrochemical performance of TAQ, Li2-TAQ, and Li4-TAQ were first assessed in conjunction with a sulfide-based solid-state electrolyte, LiePSsCl (LPSC1), using the cell structure shown in FIG. 10A. Li metal was used as the anode and silver-carbon (Ag-C) was used asan interlayer between Li metal and the separator. All cells exhibited similar voltage profiles, featuring two pseudo-plateaus upon the discharge and three pseudo-plateaus upon the charge (FIGS. 10B-10D).

[0056] During the chargc / dischargc cycle, each TAQ molecule could reversibly insert and extract four Li+ions, regardless of its initial oxidized or reduced state. The OCV of solid cells decreased from 2.8 V to 2.6 V and then to 1.6 V when TAQ, Li2-TAQ, and Li4-TAQ were used as the active material, respectively. The cells based on TAQ and Lii-TAQ delivered specific capacities exceeding the theoretical values, whereas the cell using Li4-TAQ delivered a specific capacity of 270 mAh / g, corresponding to 83% of material utilization. The extra capacity observed for TAQ and Li2-TAQ was likely attributed to the chemical reaction with LPSC1, as further explained below in FIGS. 12A-12B.

[0057] Solid-state cells using electrode composites with variable cathode fractions were assembled and investigated for both TAQ and Li4-TAQ (FIG. 12A). At the cathode fraction of 40 wt.%, both cells exhibited high material utilization of 100% for TAQ and 83% for Li4-TAQ. Increasing the cathode fraction to 50 wt.% and to 60 wt.% did not significantly affect the material utilization of TAQ. However, when the cathode fraction was increased to 70 wt.%, a significant drop in the utilization to 25% was observed, due to insufficient ionic percolation in the composite electrode because of the low ionic conductivity of TAQ. In contrast, Li4-TAQ was able to maintain 62% of material utilization at a 70 wt.% cathode fraction, due to its high ionic conductivity that ensures sufficient ionic percolation in the composite electrode.

[0058] The electrode-level specific energies of TAQ and Li4-TAQ as a function of cathode fraction are summarized in FIG. 11B. Both TAQ and Li4-TAQ showed increased energy as the cathode fraction rose from 40 wt.% to 50 wt.% and 60 wt.%. At 70 wt.%, the electrode-level specific energy decreased to 122 Wh / kg for TAQ, while that of Li4-TAQ remained above 300 Wh / kg. Overall, the highest energy of 446 Wh / kg was achieved by TAQ at 60 wt.% cathode fraction, likely including some contribution from decomposed sulfide redox species.

[0059] The chemical stability between LPSC1 and TAQ was investigated by grinding powders of both materials in the presence of tetrahydrofuran to facilitate the reaction (FIG. 12A). ATR-FTIR was employed to characterize the obtained powders after drying. The corresponding IR spectrum revealed a significant reduction in the intensity of N-H bands in the region of 3200-3500 cm’1, along with a complete disappearance of carbonyl band around 1620 cm’1. The fingerprint of this spectrum was very close to that of Li4-TAQ, indicating that TAQ was completely reduced to Li4-TAQ upon mixing-lowith LPSC1. Consequently, sulfide species in LPSC1 are expected to undergo oxidation reaction, generating redox-active lithium poly-thiophosphates (Li-PSn), as previously demonstrated with PTO (Ref. 2). The same analysis holds true for Li2-TAQ upon mixing with LPSC1 under the same condition. However, Li4-TAQ was found to be stable upon mixing with LPSC1, as no apparent change was observed in the IR spectrum of the Li4-TAQ / LPSC1 powder when compared to pristine L14-TAQ.

[0060] The interfacial resistance in fresh electrodes based on TAQ and Li4-TAQ were investigated by Electrochemical Impedance Spectroscopy (EIS) and corresponding distribution of relaxation time (DRT) (FIG. 12B). A cathode fraction of 70 wt.% was deliberately chosen to highlight the differences between TAQ and Li4-TAQ. The as-obtained DRT plots revealed a low peak intensity for Li4-TAQ with the time constant (r) ranges of 1-10 s and 0.01-1 s, indicating low diffusion resistance and interfacial resistance, respectively. In contrast, TAQ exhibited peak intensities that were orders of magnitude higher, reflecting higher diffusion resistance and interfacial resistance.

[0061] The rate performance of TAQ and Li4-TAQ with different cathode fractions are shown in FIGS. 13A-13D. At 40 wt.% fraction, both TAQ and Li4-TAQ batteries achieved over 80% capacity retention at 0.5C. Li4-TAQ exhibited superior rate capability at higher cathode fractions compared to TAQ, maintaining 79% and 75% capacity retention at 0.5C with 50 wt.% and 60 wt.% cathode fractions, respectively. In contrast, TAQ obtained only 42% and 12% retention at 0.5C at 50 wt.% and 60 wt.%.

[0062] In terms of cycling stability, Li4-TAQ demonstrated superior performance compared to TAQ and Li2-TAQ (FIGS. 14A-14D). All cells were tested at 0.5 C. At a cathode fraction of 40 wt.%, the capacity retentions after 200 cycles were 65.2% for TAQ, 70.3% for Li2-TAQ, and 82.5% for IJ4- TAQ (FIG. 14A). The cycling performance of Li4-TAQ remained competitive even with increasing cathode fraction, retaining 87.9% of its capacity after 200 cycles at 50 wt.% and 83.0% after 200 cycles at 60 wt.% (FIG. 14B). While TAQ with 50 wt.% and 60 wt.% cathode fractions achieved capacity retention of only 23.6% and 25.7%, respectively (FIG. 14C). High areal capacities (>1 mAh / cm2) were achieved for Li4-TAQ and TAQ using cathode loadings of 20 and 12 mg / cm2, respectively (FIG. 14D).

[0063] The solid-state electrochemical performance of TAQ, Li2-TAQ, and Li4-TAQ were further evaluated in combination with a halide electrolyte, LiaYCLs, using the cell structure shown in FIG. 15 A. Due to the high voltage stability of halide electrolyte, the OCV for the cell using TAQ revealeda value of 3.2 V, which was 400 mV higher compared to a similar cell using sulfide electrolyte (FIGS. 15B-15D). The higher voltage reflects the negligible chemical reaction between TAQ and LLYCk, compared to that with sulfide. The as-obtained voltage profiles revealed a four-electron redox reaction with an average voltage of 2.32 V. However, cells using both Lio-TAQ and Li4-TAQ displayed mediocre performances characterized by large overpotential and low specific capacity. The underlying poor performance is ascribed to non-ideal electrode micro structure and further electrode optimization is required to enhance the performance.

[0064] The performance of TAQ-based solid-state batteries under varying stack pressures is shown in FIGS. 16A-16C. Compared to the cell operated at 14 MPa, reducing the stack pressure to 2 MPa and 1 MPa has minimal impact on the battery performance, since all voltage profiles exhibit similar features with specific capacities exceeding 380 mAh / g (FIG. 16A). Likewise, the rate capability remains largely unaffected by low stack pressures (FIG. 16B). At low C-rates of 0.1C and 0.2C, all cells exhibit comparable capacities, regardless of the applied stack pressure. As the C-rate increases to 0.3C and 0.5C, cells operating at 2 MPa and 1 MPa show a slight decrease in capacity compared to those at 14 MPa, with this effect becoming more pronounced at higher C-rates of 0.66C and 1C. Nevertheless, the cell cycled under 1 MPa retains 68%, 61%, and 50% of its capacity at 0.5C, 0.66C, and 1C, respectively, relative to its capacity at 0.1C. The inherent malleability of TAQ enables reduced stack pressure on cycling stability, as shown in FIG. 16C. After 150 cycles, comparable capacity retentions of 86.0%, 88.0% and 74.5% are attained under stack pressures of 14 MPa, 2 MPa and 1 MPa, respectively.

[0065] Operando SEM was performed on the cross-section of a TAQ-based miniature solid-state cell cycled at 0.2 MPa to visualize the morphology evolution of TAQ electrode. The as-obtained voltage profile and corresponding cross-sectional SEM images at various states of charge (SoCs) are presented in FIGS. 17A-17B, respectively. Despite the ultralow stack pressure, the voltage profile exhibits similar features as the one obtained from the die cell, confirming that operando imaging of the electrode can be performed under practical conditions. Owing to its malleability, TAQ domains in the electrode maintain intimate contact with LPSC1 domains across all SoCs. The electrode retains its dense structure throughout the charge / discharge cycles without developing porosity or exhibiting any apparent mechanical degradation.

[0066] To quantify the volume change of TAQ particles during cycling, Applicant monitored the cross-sectional area evolution of three individual TAQ particles in the electrode over a complete chargc / dischargc cycle (FIGS. 18A-18B). The corresponding overall size evolution as a function of SoC for TAQ is depicted in FIG. 18C. During the discharge process, the TAQ particle exhibits continuous expansion, with an estimated volume change of 5%. Upon charge, the particle contracts to the same extent, demonstrating an overall volume change of 5%.

[0067] Example 1.1. Materials and methods

[0068] The following chemicals and solvents were purchased and used from commercial suppliers without further purification. Tetraaminobenzoquinone (TABQ) was synthesized following a previous report (Ref. 6). Tetrabutylammonium chloride (97%, Sigma- Aldrich), acetonitrile (HPLC grade, Thermo Chemical), dimethylformamide (HPLC grade, Thermo Chemical), methanol (HPLC grade, Thermo Chemical), dimethoxyethane (anhydrous, Sigma- Aldrich), and tetrahydrofuran (anhydrous, Sigma- Aldrich) were purchased from various vendors. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectra were recorded on a Thermo Scientific Nicolet iS5 spectrometer. Magic angle spinning (MAS)7Li nuclear magnetic resonance (NMR) was performed on a JEO1 ECA-500 instrument using 3.2 mm zirconia rotor at a spinning rate of 10 kHz with a single pulse. Powder X-ray diffraction (PXRD) patterns were recorded using a Smail Lab diffractometer equipped with a 9 / 20 reflection geometry and PhotonMax high-flux 9 kW rotating anode X-ray source using Cu Ka radiation (Kai = 1.5406 A, Ka2 = 1.5444 A, Ka2 / Kai = 0.5). The tube voltage and current were 45 kV and 200 mA, respectively. Samples for PXRD were prepared by placing TAQ and lithiated TAQ powder in an air-tight sample holder with zero diffraction single crystal silicon plate (MTI). The data were recorded in 20 range of 10-60° with a step width of 0.01° and a scan rate of l° / min. Electron Paramagnetic Resonance (EPR) spectra were recorded on bench-top Magnettech ESR5000 spectrometer at 300 K using a quartz capillary filled with 20-25 mg of sample. The capillaries were prepared inside an mBraun argon-filled glovebox with oxygen level < Ippm, septum-sealed and then covered with epoxy glue for efficient protection from air. The magnetic field was swept from 328 to 345 mT; the microwave power P was 0.45 mW, the amplitude Bmwas 0.1 mT, the modulation frequency was 100 kHz, and the acquisition time was 60 s. All EPR spectra were normalized by weight of sample.

[0069] Bis-tetraaminobenzoquinone (TAQ) was synthesized by one-step Michael addition and elimination of the precursor TABQ according to the previously reported solvothermal method (Ref. 6). To a 500 mL Schlenk flask was added 250 mL of dimethylformamide followed by 37.6 g of tetrabutylammonium chloride. The obtained mixture was sonicated until the formation of a colorless clear solution. Next, 4 g of TABQ was added to the mixture and heated in an oil bath at 85 °C for one night. Then the mixture was cooled down naturally, filtered off, washed thoroughly with dimethylformamide and methanol. The resulting dark-greenish black solid was dried under vacuum oven at 80 °C overnight to give TAQ. Yield: 35 %. v = 3464, 3403, 3341, 3287, 3228, 1651, 1620, 1518, 1461, 1345, 1234, 1184, 1130, 1026, 718, 656, 585 cm"1.

[0070] Lix-TAQ were synthesized by chemical lithiation using lithium naphthalene solution. First, 0.25 M lithium naphthalene solution was prepared by dissolving 481 mg of naphthalene crystals in 15 mL of anhydrous dimethoxyethane. Then 30 mg of lithium metal was added to the mixture leading to the formation of dark-green solution, indicating the formation of lithium naphthalene radical complex. The as-obtained mixture was kept stirring at room temperature overnight to complete the reaction. Second, 7.8 mL of lithium naphthalene solution was added to 300 mg of TAQ and the obtained mixture was kept stirring at room temperature overnight. Then the solid was isolated by centrifugation and washed thoroughly with dimethoxyethane to remove any excess of lithium naphthalene. The solid was dried under vacuum at 120 °C for 20 h to give Li2-TAQ as dark purple powders in a quantitative yield. Li2-TAQ powder is air-sensitive and can be completely self-oxidized to TAQ after exposure to air for one night. The whole procedure was carried out inside the glovebox, v = 3417, 3313, 3218, 2979, 1478, 1385, 1250, 1165, 1052, 872, 812, 696 cm’1.

[0071] A similar procedure was used to synthesize Li4-TAQ. In a typical synthesis, 300 mg of TAQ was added to 23.8 mL of lithium naphthalene solution and kept stirring at room temperature overnight. The solid was isolated by centrifugation and washed thoroughly with dimethoxyethane to remove any excess of lithium naphthalene. The solid was then dried under vacuum at 120 °C for 20 h to give Li4- TAQ as a dark brown powder in a quantitative yield. Li4-TAQ powder is air-sensitive and can be completely self-oxidized to TAQ after exposure to air overnight, v = 3325, 3247, 2920, 2830, 2771, 1594, 1464, 1345, 1293, 1227, 1168, 1052, 932, 822, 597 cm’1.

[0072] For the evaluation of chemical stability between TAQ, Li2-TAQ, L14-TAQ powders and sulfide electrolyte (LiePSsCl, NEI Inc.), 20 mg of active material was first dispersed in 5 mL of anhydroustetrahydrofuran and kept under stirring at room temperature for 30 minutes. A small portion of the resulting dispersion was added to LPSC1 powders and grinded in an agate mortar until dry powders were obtained. The powders were further dried under vacuum at 80 °C overnight. The whole procedure was conducted inside the glovebox. The as-obtained samples were characterized by FTIR using a sample holder covered with Kapton foil to prevent exposure to air.

[0073] For cell preparation and electrochemical measurements, all electrode composites and cells were prepared and assembled in an mBraun argon-filled glovebox (<0.5 ppm water and oxygen content). Electrochemical measurements were recorded either on Bio-Logic VMP3 or Neware.

[0074] For galvanostatic charge / discharge tests in liquid electrolyte, active material (TAQ, Li2-TAQ, or Li4-TAQ), Ketjenblack carbon (KB600, MSE), and polytetrafluoroethylene (PTFE, Sigma Aldrich) binder were mixed in a 6:3:1 mass ratio in an agate mortar for 20 minutes. The resulting electrode composites were then directly used without any additional treatment. Coin cells were assembled using electrodes with areal mass loading of 5 mg / cm2as cathodes, glass fiber separator (Whatman, Grade GF / A) impregnated with 70 pL of LP30 electrolyte, and lithium foil as anode. The cells were cycled within the voltage window of 1.5-3.5 V vs. Li+ / Li at room temperature using 0.1 C as cycling rate.

[0075] For Li-ion conductivity measurements in an electron-blocking symmetrical cell that includes Li|solid electrolyte|active material|solid electrolyte|Li (FIG. 9A), samples were prepared by cold pressing 100 mg of active material powder at 375 MPa for 5 min to form a pellet, then 20 mg of LPSC1 was spread on both sides of the pellet and pressed together at 375 MPa for another 5 min. Finally, lithium metal foil (60 pm) was added on each side to serve as lithium reservoir. The symmetrical cell was transferred inside a climatic chamber for variable temperature conductivity measurements. The conductivity measurements were carried out according to the d.c. current- voltage technique using SP300 Biologic potentiostat. The activation energy was calculated from the slope of the corresponding Arrhenius plot.

[0076] For galvanostatic charge / discharge tests in solid-state cells, active material (TAQ, Lii-TAQ, or Li4-TAQ), LPSC1, and vapor-grown carbon fiber (VGCF, PR-19-XT-HHT, Applied Sciences) were mixed using an agate mortar and pestle with mass fraction of x:(95-x):5, where the value of x are 40, 50, 60 and 70. The resulting cathode composites were then directly used without any additional treatment. Solid-state cells were assembled using a cylindrical custom-made polyetherether-ketone (PEEK) die cell with an inner diameter of 13 mm along with two titanium rods. First, 100 mg of LPSC1powder was placed inside the die cell and cold pressed at 150 MPa for 2 minutes to form the separator. Next, 5 mg of cathode composite was uniformly distributed on one side while a silver-carbon interlayer (Ag-C, 20 pm) was added to the other side of the separator, followed by pressing at 375 MPa for 15 minutes. Finally, a lithium metal foil (60 pm) attached to a stainless steel (50 pm) current collector was added on top of the Ag-C interlayer.

[0077] A similar procedure was used for assembling solid-state cells based on halide-based solid electrolyte, but with a two-layer solid separator. Active material (TAQ, Lii-TAQ, or Li4-TAQ), LiaYCle, and vapor-grown carbon fiber (VGCF, PR-19-XT-HHT, Applied Sciences) were mixed using an agate mortar and pestle with mass fraction of 40:50:10. Briefly, 50 mg LiePSsCl was first pressed at 150 MPa for 2 minutes, then 100 mg of LiaYCle was added and pressed at 150 MPa for another 2 minutes. Next, 5 mg of cathode composite and Ag-C interlayer (20 pm) were added on the top of halide and sulfide sides, respectively, and then pressed at 375 MPa for 15 minutes. Finally, a lithium metal foil (60 pm) attached to a stainless steel (50 pm) current collector was added on top of the Ag-C interlayer.

[0078] The as-assembled solid cells were cycled at 60 °C within the potential window of 1.5-3.5 V vs. Li+ / Li using cycling rates from 0.1 C to 0.5 C. For high mass loading cells, 15 mg of TAQ and 25 mg of L14-TAQ cathode composites were used, and the voltage window was optimized to 1.5-3.2 V vs. Li+ / Li.

[0079] Electrochemical impedance spectroscopy (EIS) was performed using SP-300 with a 10 mV a.c. perturbation voltage in the frequency range of 1 MHz to 0.1 Hz and data was collected at the rate of 6 points per decade. The distribution of relaxation times (DRT) was estimated by deconvoluting the EIS spectra using a MATLAB code.

[0080] The operando SEM was carried out using an air-free vessel (Solid Design Instruments, Model FV-003A). Briefly, a complete solid-state cell was extracted from PEEK die and then trimmed into a 3 mm x 3 mm x4 mm miniature cell using a razor blade. One side of the cell was polished using an Argon-ion beam cross-section polisher (IB-19520CCP, JEOL, USA) at -30 °C to prevent heat damage. The polished miniature cell was loaded in the air-free vessel, which was subsequently transferred to a scanning electron microscope (Axia ChemiSEM) chamber. The cell was connected to a potentiostat (Biologic SP300) via a feedthrough for electrochemical measurements. A small stack pressure of 0.2 MPa was applied using a calibrated plastic bolt and torque screwdriver. SEM imageswere captured every 15 minutes at the same location. MATLAB code was employed to generate videos integrating the SEM images with the electrochemical cycling data.

[0081] For the particle size evolution analysis, we first crop images containing individual particles from a sequence of SEM images. The “Trainable Weka Segmentation” tool in ImageJ was then used to distinguish between the active material particles and the solid electrolyte particles. Next, Applicant generated binary images from the segmentation results. The “Analyze Particles” tool in ImageJ was subsequently applied to quantify the area of the active material in each image. For both samples, three independent particles were tracked and measured to obtain the statistic results.

[0082] References1. Zhao et al., "Roadmap of Solid-State Lithium-Organic Batteries toward 500 Wh kg-1" ACS Energy Lett. 2021, 6, 3287-33062. Zhang et al., "Microstructure engineering of solid-state composite cathode via solvent-assisted processing" Joule, 2021, 5, 1845-18593. Hao et al., “Taming Active Material-Solid Electrolyte Interfaces with Organic Cathode for All- Solid-State Batteries" Joule, 2019, 3, 1349-13594. Dinca et al., Fused aromatic molecules as electrode materials, WO 2023022750 Al5. Chen et al., "High-rate, high-capacity electrochemical energy storage in hydrogen-bonded fused aromatics" Joule, 2023, 7, 1-176. Chen et al., "A Layered Organic Cathode for High-Energy, Fast-Charging, and Long-Lasting Li- Ion Batteries" ACS Cent. Sci., 2024, 10, 3, 569-578

[0083] Without further elaboration, it is believed that one skilled in the art can, using the description herein, utilize the present disclosure to its fullest extent. The embodiments described herein arc to be construed as illustrative and not as constraining the remainder of the disclosure in any way whatsoever. While the embodiments have been shown and described, many variations and modifications thereof can be made by one skilled in the art without departing from the spirit and teachings of the invention. Accordingly, the scope of protection is not limited by the description set out above, but is only limited by the claims, including all equivalents of the subject matter of the claims. The disclosures of all patents, patent applications and publications cited herein are hereby incorporated herein by reference, to the extent that they provide procedural or other details consistent with and supplementary to those set forth herein.

Claims

CLAIMS1. An electrode comprising a molecule selected from the group consisting of, a derivative thereof, a tautomer thereof, an oligomer thereof, or combinations thereof, wherein M is a metal.

2. The electrode of claim 1, wherein M is an alkali metal selected from the group consisting of Li,Na, K, or combinations thereof.

3. The electrode of claim 1, wherein the molecule constitutes at least 40 wt.% of the electrode.

4. The electrode of claim 1, wherein the molecule constitutes at least 60 wt.% of the electrode.

5. The electrode of claim 1, wherein the electrode comprises an anode.

6. The electrode of claim 1, wherein the electrode comprises a cathode.

7. The electrode of claim 6, wherein the cathode is a component of an electrochemical cell.

8. The electrode of claim 7, wherein the electrochemical cell is a solid-state battery.

9. The electrode of claim 8, wherein the solid-state battery comprises: the cathode comprising the molecule, an anode, anda solid electrolyte between the cathode and the anode.

10. An electrochemical cell comprising a cathode, wherein the cathode comprises a molecule selected from the group consisting of:derivative thereof, a tautomer thereof, an oligomer thereof, or combinations thereof, wherein M is a metal.

11. The electrochemical cell of claim 10, wherein the electrochemical cell further comprises a solid electrolyte.

12. The electrochemical cell of claim 11, wherein the solid electrolyte is a sulfide or halide-based solid electrolyte.

13. The electrochemical cell of claim 11, wherein the solid electrolyte is a catholyte comprising at least one inorganic compound that is ion-conducting.

14. The electrochemical cell of claim 13, wherein the at least one inorganic compound has a formula of AxByCz, wherein A is selected from the group consisting of Li, Na, K or combinations thereof, wherein B is selected from the group consisting of B, N, P, Si, As, Sc, Y, In, Zr, or combination thereof, and wherein C is selected from the group consisting of O, S, Se, F, Cl, Br, 1 or combination thereof.

15. The electrochemical cell of claim 11, wherein the electrochemical cell comprises an electrolyte layer that is entirely inorganic.

16. The electrochemical cell of claim 11, wherein the electrochemical cell further comprises an interlayer comprising Ag and carbon.

17. The electrochemical cell of claim 11, wherein the electrochemical cell further comprises an anode.

18. The electrochemical cell of claim 17, wherein the anode comprises a metal-based anode, an alkali metal, an anode-free configuration, or combinations thereof.

19. The electrochemical cell of claim 10, wherein M is an alkali metal selected from the group consisting of Li, Na, K, or combinations thereof.

20. The electrochemical cell of claim 10, wherein the molecule constitutes at least 40 wt.% of the cathode.

21. The electrochemical cell of claim 10, wherein the molecule constitutes at least 60 wt.% of the cathode.

22. The electrochemical cell of claim 10, wherein the electrochemical cell is a solid-state battery.

23. The electrochemical cell of claim 22, wherein the solid-state battery comprises: the cathode comprising the molecule, an anode, and a solid electrolyte between the cathode and the anode.

24. A molecule selected from the group consisting ofderivative thereof, a tautomer thereof, an oligomer thereof, or combinations thereof, wherein M is a metal.

25. The molecule of claim 24, wherein M is an alkali metal selected from the group consisting of Li, Na, K, or combinations thereof.

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