Sodium antimony telluride electrode material for solid-state batteries

Abstract

The present disclosure provides a composition comprising a sodium matrix and antimony telluride particles distributed throughout, configured to facilitate sodium stripping from a bulk portion during electrochemical cycling. The antimony telluride particles may comprise Sb2Te3 and have an average particle size of less than 10 pm. The composition facilitates sodium replating into areas where pores have formed during stripping and enhances interfacial stability with a NASICON solid electrolyte. Also provided is a solid-state battery comprising a solid electrolyte and an electrode comprising the sodium matrix and antimony telluride particles, wherein the electrode maintains interfacial stability with the solid electrolyte during electrochemical cycling by facilitating sodium stripping from a bulk portion.

Description

[0001] Princeton - 104976

[0002] SODIUM ANTIMONY TELLURIDE ELECTRODE MATERIAL FOR SOLID-STATE

[0003] BATTERIES

[0004] CROSS-REFERENCE TO RELATED APPLICATIONS

[0005] This application claims priority7to U.S. Provisional Application No. 63 / 723,936, filed November 22, 2024, which is hereby incorporated by reference in its entirety.

[0006] STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0007] This invention was made with government support under Grant No. DE-SC0023438 awarded by the Department of Energy. The government has certain rights in the invention.

[0008] TECHNICAL FIELD

[0009] The present disclosure relates to electrode materials for energy storage devices, and more particularly to a sodium antimony telluride electrode material for solid-state battery applications that enables sodium stripping from bulk portions and enhanced interfacial stability with solid electrolytes.

[0010] BACKGROUND

[0011] Solid-state batteries represent an emerging technology in energy storage systems that utilize solid electrolytes instead of liquid electrolytes found in conventional batteries. These systems offer potential advantages including enhanced safety profiles, improved thermal stability, and the possibility of higher energy densities. However, the development of solid- state batteries faces various technical challenges related to interfacial stability, ion transport, and electrode-electrolyte compatibility.

[0012] Sodium-based battery technologies have gained attention as alternatives to lithium- based systems due to the abundance and lower cost of sodium resources. Sodium-ion batteries can potentially provide cost-effective energy storage solutions for various applications, including grid-scale storage and electric vehicles. The development of sodium-based solid- state batteries combines the potential benefits of both sodium chemistry and solid-state architecture.

[0013] One of the primary challenges in solid-state battery development involves maintaining stable interfaces between electrodes and solid electrolytes during charge and discharge cycles. Traditional electrode materials may experience issues such as contact loss, interfacial Princeton - 104976 resistance grow th, and mechanical degradation during cycling. These phenomena can lead to reduced battery performance, shorter cycle life, and decreased efficiency.

[0014] The stripping and plating behavior of metal electrodes in solid-state systems differs from that observed in liquid electrolyte systems. In solid-state configurations, the absence of liquid electrolyte changes the mechanisms by which metal ions are transported and deposited. Understanding and controlling these processes is important for developing stable and efficient solid-state battery systems.

[0015] NASICON (sodium superionic conductor) materials are commonly used as solid electrolytes in sodium-based solid-state batteries due to their ionic conductivity properties. However, achieving stable interfacial contact between sodium metal electrodes and NASICON electrolytes remains a technical challenge that affects overall battery performance and cyclability.

[0016] Current approaches to addressing interfacial stability in solid-state batteries include various surface treatments, buffer layers, and composite electrode designs. These methods aim to improve contact between electrodes and solid electrolytes while maintaining electrochemical performance during repeated cycling.

[0017] SUMMARY

[0018] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

[0019] According to an aspect of the present disclosure, a composition of matter is provided. The composition of matter comprises a sodium matrix and a plurality of antimony telluride particles distributed throughout the sodium matrix. The composition of matter may be configured to facilitate sodium stripping from a bulk portion of the composition of matter during electrochemical cycling. Facilitating may include not utilizing any components that would hinder the process in question (here, sodium stripping). This may include, e.g., not utilizing coatings or treatments that reduce sodium conductivity, such as incorporate an inorganic coating (such as a ceramic), or a polymeric coating with low sodium conductivity. This configuration enables improved electrochemical performance by allowing sodium extraction from the entire electrode volume rather than being limited to surface interactions, thereby enhancing capacity utilization and cycling stability. Princeton - 104976

[0020] According to other aspects of the present disclosure, the composition of matter may include one or more of the following features. The plurality of antimony telluride particles may be substantially evenly distributed throughout the sodium matrix. This uniform distribution promotes consistent electrochemical behavior across the electrode and prevents localized current concentrations that could lead to performance degradation.

[0021] The plurality of antimony telluride particles may have an average particle size of less than 10 pm. This particle size range provides an optimal balance between surface area for electrochemical activity and mechanical stability within the sodium matrix.

[0022] The plurality7of antimony telluride particles may have an average particle size of less than 5 pm. This smaller particle size further enhances the interfacial contact area and improves the uniformity of electrochemical reactions throughout the electrode.

[0023] The antimony telluride particles may comprise Sb2Tes. This specific composition provides the desired electrochemical properties and chemical stability within the sodium matrix environment.

[0024] The composition of matter may be configured to facilitate sodium re-plating into areas where pores have formed during stripping. This may include, e.g., selecting a composition of matter that forms sodiophilic surfaces in the pore interiors. This self-healing mechanism helps maintain electrode integrity7and prevents the accumulation of voids that could compromise performance over extended cycling.

[0025] The composition of matter may be configured to enhance interfacial stability with a NASICON solid electrolyte. This enhanced stability reduces interfacial resistance and maintains electrical contact during repeated charge-discharge cycles, leading to improved battery longevity.

[0026] The NASICON solid electrolyte may comprise NasZr2Si2POi2. This specific electrolyte composition provides high ionic conductivity and chemical compatibility with the sodium antimony telluride electrode material.

[0027] According to another aspect of the present disclosure, a solid-state battery7is provided. The solid-state battery comprises a solid electrolyte and an electrode comprising a sodium matrix and a plurality' of antimony telluride particles distributed throughout the sodium matrix. The electrode is configured to maintain interfacial stability with the solid electrolyse during electrochemical cycling by facilitating sodium stripping from a bulk portion of the electrode. This design eliminates the safety7concerns associated with liquid electrolytes while providing stable long-term cycling performance through the bulk stripping mechanism. Princeton - 104976

[0028] According to other aspects of the present disclosure, the solid-state battery may include one or more of the following features. The solid electrolyte may comprise a NASICON material. NASICON materials provide high sodium ion conductivity and chemical stability, making them suitable for solid-state sodium battery applications.

[0029] The NASICON material may comprise Na3Zr2Si2POi2. This specific NASICON composition offers optimal ionic conductivity and mechanical properties for solid-state battery operation.

[0030] The plurality of antimony telluride particles may be substantially evenly distributed throughout the sodium matrix. This uniform distribution ensures consistent electrochemical performance across the electrode surface and prevents localized degradation.

[0031] The plurality of antimony telluride particles may have an average particle size of less than 10 pm. This particle size provides effective modification of the sodium matrix properties while maintaining processability and structural integrity'.

[0032] The electrode may be configured to facilitate sodium re-plating into areas where pores have formed during stripping. This capability helps maintain electrode density and prevents the formation of large voids that could lead to contact loss with the solid electrolyte.

[0033] The electrode may comprise an anode. As an anode material, the composition provides stable sodium metal cycling with enhanced interfacial properties compared to pure sodium metal.

[0034] According to another aspect of the present disclosure, a method of operating a solid- state battery is provided. The method comprises providing a solid-state battery comprising a solid electrolyte and an electrode, wherein the electrode comprises a sodium matrix and a plurality of antimony telluride particles distributed throughout the sodium matrix. The method further comprises applying an electrical potential to the electrode to initiate sodium stripping from a bulk portion of the electrode, and facilitating sodium re-plating into areas where pores have formed during the stripping. This operating method enables stable cycling with minimal interfacial degradation and maintains electrode-electrolyte contact throughout the battery's operational life.

[0035] According to other aspects of the present disclosure, the method may include one or more of the following features. The solid electrolyte may comprise a NASICON material. NASICON materials provide the ionic conductivity and stability needed for effective solid- state battery' operation.

[0036] The NASICON material may comprise Na3Zr2Si2POi2. This composition offers optimal performance characteristics for sodium-based solid-state batteries. Princeton - 104976

[0037] The plurality of antimony telluride particles may have an average particle size of less than 10 pm. This particle size range provides effective electrochemical modification while maintaining electrode processability.

[0038] The antimony telluride particles may comprise SbzTes. This composition provides the desired electrochemical and chemical properties for stable battery operation.

[0039] The method may further comprise maintaining interfacial stability’ between the electrode and the solid electrolyte during electrochemical cycling. This stability maintenance prevents performance degradation and extends battery cycle life.

[0040] According to another aspect of the present disclosure, a method of manufacturing an electrode for a solid-state battery is provided. The method comprises providing a sodium matrix, distributing a plurality of antimony telluride particles throughout the sodium matrix to form a composite electrode material, and configuring the composite electrode material to facilitate sodium stripping from a bulk portion of the composite electrode material during electrochemical cycling. This manufacturing approach enables the production of electrodes with enhanced electrochemical properties and improved interfacial stability compared to conventional sodium metal electrodes.

[0041] According to other aspects of the present disclosure, the manufacturing method may include one or more of the following features. Distributing the plurality’ of antimony telluride particles may comprise substantially evenly distributing the particles throughout the sodium matrix. This uniform distribution ensures consistent electrode properties and performance across the entire electrode area.

[0042] The plurality of antimony telluride particles may have an average particle size of less than 10 pm. This particle size facilitates effective integration into the sodium matrix while providing the desired electrochemical modifications.

[0043] The antimony telluride particles may comprise Sb2Te?. This specific composition provides optimal electrochemical and chemical compatibility with the sodium matrix.

[0044] The method may further comprise configuring the composite electrode material to enhance interfacial stability yvith aNASICON solid electrolyte. This configuration step ensures optimal performance when the electrode is integrated into a complete solid-state battery system.

[0045] The foregoing general description of the illustrative embodiments and the folloyving detailed description thereof are merely exemplary' aspects of the teachings of this disclosure and are not restrictive. Princeton - 104976

[0046] The foregoing general description of the illustrative embodiments and the following detailed description thereof are merely exemplary aspects of the teachings of this disclosure and are not restrictive.

[0047] BRIEF DESCRIPTION OF FIGURES

[0048] Non-limiting and non-exhaustive examples are described with reference to the following figures.

[0049] FIG. 1 illustrates a schematic representation of an electrode for solid-state battery applications, according to aspects of the present disclosure.

[0050] FIG. 2A depicts a graph showing voltage versus time for cycling at 0.5 mAh / cm2capacity, according to an embodiment.

[0051] FIG. 2B depicts a graph showing voltage versus time for cycling at 1.0 mAh / cm2capacity, according to an embodiment.

[0052] FIG. 2C depicts a graph showing voltage versus time for cycling at 2.0 mAh / cm2capacity, according to an embodiment.

[0053] FIG. 3A depicts a graph showing voltage as a function of time during electrochemical cycling at 2.5 MPa, according to aspects of the present disclosure.

[0054] FIG. 3B depicts a Nyquist plot showing impedance spectra data at 2.5 MPa, according to aspects of the present disclosure.

[0055] FIG. 4A depicts a graph showing voltage as a function of time during electrochemical cycling at 5 MPa, according to aspects of the present disclosure.

[0056] FIG. 4B depicts a Nyquist plot showing impedance spectra data at 5 MPa, according to aspects of the present disclosure.

[0057] DETAILED DESCRIPTION

[0058] The following description sets forth exemplary aspects of the present disclosure. It should be recognized, however, that such description is not intended as a limitation on the scope of the present disclosure. Rather, the description also encompasses combinations and modifications to those exemplary aspects described herein.

[0059] The mechanism governing sodium transport and interface stabilization in the presently disclosed solid-state Na-Sb-Te system is fundamentally distinct from that reported for more conventional liquid-electrolyte NST-Na composites. In conventional approaches, the sodium- antimony-telluride intermetallic primarily serves as a chemically stable, sodiophilic scaffold embedded within metallic sodium under liquid-electrolyte conditions. Stabilization in Princeton - 104976 that system arises from thermodynamic wetting at the metal-intermetallic interface. Density functional theory (DFT) simulations and cryogenic microscopy demonstrated that individual sodium atoms are energetically stabilized on the surface of the Naz St eTes / sVaci / s) phase, promoting uniform planar deposition. This wetting-driven process suppresses dendrite formation and minimizes SEI grow th by enabling conformal sodium plating and stripping within a porous, vacancy-rich intermetallic matrix. Thus, in the liquid configuration, the NST material functions as a static wetting scaffold, where stability is governed primarily by chemical affinity rather than structural or mechanical adaptation.

[0060] In contrast, the mechanism operating in the present solid-state Na-Sb-Te | NaSICON system is governed by an electro-chemo-mechanical grain-boundary stabilization process, distinct from the wetting-controlled behavior observed under liquid conditions. When interfaced with a solid NaSICON (Na3Zr2Si2POi2) electrolyte, the Na-Sb-Te phase does not simply act as an inert buffer layer. Instead, dispersed Sb-Te particles embedded within the metallic sodium matrix alter the grain boundary structure and energy landscape of the sodium phase. This microstructural modification enhances the uniformity and mobility of sodium-ion transport along and across grain boundaries during plating and stripping. Operando analysis reveals that sodium extraction and redeposition occur homogeneously within this modified matrix, thereby reducing localized stress accumulation and void formation at the electrodeelectrolyte interface. The embedded intermetallic particles act as nucleation regulators and current distributors, promoting uniform grain-by-grain dissolution and deposition. As a result, the solid-state system achieves highly stable plating and stripping behavior without significant interfacial resistance growth or contact degradation. Unlike the liquid NST-Na system, where stability is derived from thermodynamic wetting and surface sodiophilicity. The solid-state design achieves interfacial integrity through microstructural regulation of the sodium host lattice, representing a fundamentally different and more robust mechanism of performance enhancement.

[0061] Therefore, unlike conventional techniques, which relies on chemical w etting in a liquid environment, the present solid-state mechanism provides structural self-adaptation and mechanical contact preservation through in-situ microstructural regulation. The novelty lies in the solid-state interfacial stabilization mechanism, wherein (i) sodium extraction occurs primarily from the electrode bulk, (ii) interfacial voids are suppressed through internal pore accommodation and grain-boundary alignment, and (iii) any localized redistribution of Te species further reinforces interfacial integrity. This coupled chemical-mechanical stabilization process enables long-term cycling stability in solid-state sodium batteries and constitutes a Princeton - 104976 distinct improvement over the wetting-controlled behavior of the previously reported liquid NST-Na svstem.

[0062] A composition of matter may comprise a sodium matrix and a plurality of antimony telluride particles distributed throughout the sodium matrix. The composition of matter may be configured to facilitate sodium stripping from a bulk portion of the composition of matter during electrochemical cycling. This configuration enables sodium extraction to occur primarily from the electrode bulk rather than being limited to interfacial regions, thereby providing enhanced cycling performance and stability7.

[0063] The plurality of antimony telluride particles may be substantially evenly distributed throughout the sodium matrix. This even distribution may be achieved through a fabrication process involving grinding antimony telluride particles into a fine powder, which is then dispersed into the sodium matrix through a series of holding and folding steps. The even distribution ensures uniform electrochemical properties throughout the composition and promotes consistent performance during battery operation.

[0064] In some cases, the plurality of antimony telluride particles have an average particle size of less than 10 pm. In other cases, the plurality of antimony telluride particles may have an average particle size of less than 5 pm. The particle size distribution of antimony telluride particles may be optimized in the fabrication process to enhance overall performance. Smaller particle sizes may provide increased surface area for interaction with the sodium matrix and may contribute to more uniform distribution throughout the composition.

[0065] The antimony telluride particles may comprise Sb2Tes. This specific composition provides the desired electrochemical and structural properties for solid-state battery applications. The Sb2Tei particles may act as nucleation regulators and current distributors within the sodium matrix, promoting controlled and uniform electrochemical processes during battery cycling.

[0066] The composition of matter may be configured to facilitate sodium re-plating into areas where pores have formed during stripping. During electrochemical cycling, sodium may be stripped from the bulk and subsequently re-plated into areas where pores have formed, effectively closing voids that develop during the stripping process. This self-healing mechanism contributes to the long-term stability and performance of the electrode material.

[0067] The antimony telluride particles may alter the grain boundary7structure and energy landscape of the sodium phase. This microstructural modification enhances the uniformity and mobility of sodium-ion transport along and across grain boundaries during plating and stripping Princeton - 104976 operations. The electrode may achieve electro-chemo-mechanical grain-boundary stabilization through microstructural regulation of the sodium host lattice.

[0068] The composition of matter may be configured to enhance interfacial stability with a NASICON solid electrolyte. The NASICON solid electrolyte may comprise Na3Zr2Si2POi2. The enhanced interfacial stability7results from the modified grain boundary structure created by the dispersed antimony telluride particles, which reduces localized stress accumulation and void formation at the electrode-electrolyte interface.

[0069] The electrode may enable uniform grain-by-grain dissolution and deposition of sodium during cycling. The embedded intermetallic particles promote uniform dissolution and deposition processes, contributing to stable plating and stripping behavior without significant interfacial resistance growth or contact degradation. The electrode may provide structural selfadaptation and mechanical contact preservation through in-situ microstructural regulation.

[0070] The sodium-to-antimony telluride ratio may be adjusted to enhance performance characteristics of the composition. This adjustment allows for optimization of the electrochemical properties and cycling stability based on specific application requirements and operating conditions.

[0071] Referring to FIG. 1, a solid-state battery may comprise a solid electrolyte and an electrode 100. The electrode 100 may comprise a sodium matrix 102 and a plurality7of antimony telluride particles 104 distributed throughout the sodium matrix 102. The electrode 100 may be configured to maintain interfacial stability with the solid electrolyte during electrochemical cycling by facilitating sodium stripping from a bulk portion of the electrode 100.

[0072] As shown in FIG. 1, the antimony telluride particles 104 are dispersed within the sodium matrix 102 to create a composite structure. The sodium matrix 102 may provide the primary conductive medium for sodium ion transport, while the antimony telluride particles 104 may7be positioned to modify the microstructural properties of the electrode 100. The arrangement of the antimony telluride particles 104 within the sodium matrix 102 may facilitate sodium stripping from bulk portions of the electrode 100 during electrochemical cycling.

[0073] The solid electrolyte may comprise a NASICON material. In some cases, the NASICON material may comprise Na3Zr2Si2PO12. The NASICON solid electrolyte may provide ionic conductivity for sodium ions while maintaining structural integrity7during battery operation. The combination of the electrode 100 with the NASICON solid electrolyte may enable solid-state battery operation without the use of liquid electrolytes. Princeton - 104976

[0074] With continued reference to FIG. 1, the electrode 100 may be configured to facilitate sodium re-plating into areas where pores have formed during stripping. During electrochemical cycling, sodium may be extracted from the bulk of the electrode 100, creating pores or voids within the structure. The electrode 100 may enable sodium to be subsequently re-plated into these areas, effectively closing the voids that develop during the stripping process. This replating mechanism may contribute to maintaining the structural integrity of the electrode 100 over multiple charge-discharge cycles.

[0075] The electrode 100 may comprise an anode in the solid-state battery configuration. As an anode, the electrode 100 may serve as the negative electrode during battery' discharge, releasing sodium ions that travel through the solid electrolyte to the cathode. The sodium matrix 102 may provide the source of sodium ions for the electrochemical reactions, while the antimony telluride particles 104 may regulate the extraction and deposition processes.

[0076] The interfacial stability between the electrode 100 and the solid electrolyte may be maintained through the modified grain boundary structure created by the antimony telluride particles 104. The particles 104 may act as current distributors and nucleation regulators, promoting uniform electrochemical processes at the interface between the electrode 100 and the solid electrolyte. This uniform behavior may reduce localized stress concentrations and prevent degradation of the electrode-electrolyte interface during repeated cycling.

[0077] The solid-state battery configuration may eliminate the need for liquid electrolytes, which can be prone to leakage and safety concerns. The solid electrolyte may’ provide a stable ionic conduction pathway while the electrode 100 maintains mechanical and electrochemical stability’ through the bulk stripping and re-plating mechanisms enabled by the antimony telluride particles 104 distributed throughout the sodium matrix 102.

[0078] A method of operating a solid-state battery may comprise providing a solid-state battery comprising a solid electrolyte and an electrode, wherein the electrode comprises a sodium matrix and a plurality of antimony’ telluride particles distributed throughout the sodium matrix. The method may further comprise applying an electrical potential to the electrode to initiate sodium stripping from a bulk portion of the electrode, and facilitating sodium re-plating into areas where pores have formed during the stripping.

[0079] The method may involve applying the electrical potential under various pressure conditions to achieve controlled sodium stripping behavior. In some cases, the electrode may operate under pressure conditions of 5 MPa during stripping operations. In other cases, the electrode may operate under pressure conditions of 10 MPa during stripping operations. These Princeton - 104976 pressure conditions may influence the uniformity and extent of sodium extraction from the bulk portion of the electrode.

[0080] The method may enable sodium stripping at low current densities without requiring applied stack pressure. In some cases, the electrode may be stripped at current densities as low as 100 pA without any applied stack pressure. This low-current operation may provide controlled and gradual sodium extraction, allowing for detailed observation and analysis of the stripping and re-plating mechanisms within the electrode structure.

[0081] The method may involve cycling the electrode at different areal capacities to accommodate various operational requirements. The electrode may be cycled at areal capacities including, e g., up to 0.5 mAh / cm2In some cases, the electrode may be cycled at areal capacities of 0.5 mAh / cm2to 1.5 mAh / cm2, such as 1.0 mAh / cm2. In other cases, the electrode may be cycled at areal capacities of 1.5 mAh / cm2to 2.5 mAh / cm2, such as 2.0 mAh / cm2. In other cases, the electrode may be cycled at areal capacities of at least 2.5 mAh / cm2. These different areal capacities may correspond to varying depths of sodium extraction and re-plating within the electrode during each cycle.

[0082] The solid electrolyte may compnse a NASICON material in the method of operating the solid-state battery. The NASICON material may provide ionic conductivity for sodium ions while maintaining structural stability' during the electrochemical cycling process. In some cases, the NASICON material may comprise NasZnSiaPO . This specific NASICON composition may offer enhanced compatibility with the sodium matrix and antimony telluride particles during the stripping and re-plating operations.

[0083] The plurality of antimony telluride particles may have an average particle size of less than 10 pm in the method of operating the solid-state battery. This particle size range may contribute to effective distribution throughout the sodium matrix and may facilitate the desired bulk stripping behavior during electrochemical cycling. The particle size may influence the nucleation and current distribution properties of the antimony telluride particles within the sodium matrix.

[0084] The antimony telluride particles may comprise Sb2Te3 in the method of operating the solid-state battery. The Sb2Tes composition may provide the electrochemical and structural properties that enable the bulk stripping mechanism and subsequent re-plating behavior. The Sb2Tea particles may act as regulators for the sodium extraction and deposition processes during the application of electrical potential.

[0085] The method may further comprise maintaining interfacial stability between the electrode and the solid electrolyte during electrochemical cycling. The interfacial stability' may Princeton - 104976 be maintained through the modified grain boundary structure created by the antimony telluride particles distributed throughout the sodium matrix. During the cycling process, the electrode may preserve mechanical and electrochemical contact with the solid electrolyte, preventing degradation that could otherwise occur from repeated sodium stripping and re-plating operations.

[0086] The facilitating of sodium re-plating into areas where pores have formed during stripping may occur through the self-healing mechanism enabled by the antimony telluride particles. As sodium is extracted from the bulk portion of the electrode, pores or voids may form within the electrode structure. The method may enable sodium to be subsequently deposited back into these pore areas, effectively closing the voids and maintaining the structural integrity of the electrode throughout the cycling process.

[0087] The method may achieve uniform electrochemical behavior through the current distribution properties of the antimony telluride particles. The particles may promote uniform grain-by-grain dissolution and deposition of sodium during the cycling process, contributing to stable performance without significant interfacial resistance growth between the electrode and the solid electrolyte.

[0088] A method of manufacturing an electrode for a solid-state battery may comprise providing a sodium matrix, distributing a plurality of antimony telluride particles throughout the sodium matrix to form a composite electrode material, and configuring the composite electrode material to facilitate sodium stripping from a bulk portion of the composite electrode material during electrochemical cycling. This manufacturing method may enable the production of electrodes with enhanced electrochemical performance and interfacial stability for solid-state battery' applications.

[0089] The method may begin with providing the sodium matrix as a base material for the electrode. The sodium matrix may serve as the primary conductive medium and may provide the structural foundation for incorporating the antimony telluride particles. The sodium matrix may be prepared in a form that allows for subsequent processing steps to achieve uniform particle distribution.

[0090] The distributing of the plurality of antimony telluride particles throughout the sodium matrix may involve grinding the antimony telluride particles into a fine powder before being dispersed into the sodium matrix. This grinding process may reduce the particle size and may create a powder form that facilitates uniform distribution within the sodium matrix. The fine powder form of the antimony telluride particles may enhance the mixing process and may contribute to achieving the desired composite structure. Princeton - 104976

[0091] The fabrication process may involve a series of holding and folding steps to ensure even distribution of the antimony telluride particles throughout the sodium matrix. These holding and folding steps may be repeated multiple times to achieve thorough mixing and uniform dispersion of the particles within the matrix material. The holding and folding technique may provide mechanical mixing that promotes homogeneous distribution while maintaining the integrity of both the sodium matrix and the antimony telluride particles.

[0092] In some cases, distributing the plurality of antimony telluride particles may comprise substantially evenly distributing the particles throughout the sodium matrix. The substantially even distribution may be achieved through the controlled holding and folding steps, which may ensure that the antimony telluride particles are dispersed uniformly rather than concentrated in localized regions. This even distribution may contribute to consistent electrochemical behavior throughout the composite electrode material during battery operation.

[0093] The plurality of antimony telluride particles may have an average particle size of less than 10 pm in the manufacturing method. This particle size range may be achieved through the grinding process and may be controlled to optimize the electrochemical properties of the resulting composite electrode material. The particle size of less than 10 pm may provide sufficient surface area for interaction with the sodium matrix while maintaining appropriate mechanical properties for the composite structure.

[0094] The antimony telluride particles may comprise SbaTes in the manufacturing method. The Sb2Tea composition may be selected for the specific electrochemical and structural properties that contribute to the bulk stripping mechanism and interfacial stability enhancement. The Sb2Tes particles may be prepared in the fine powder form through grinding before being incorporated into the sodium matrix through the holding and folding process.

[0095] The method may further comprise configuring the composite electrode material to facilitate sodium stripping from the bulk portion of the composite electrode material during electrochemical cycling. This configuration may be achieved through the controlled distribution of the antimony telluride particles, which may modify the microstructural properties of the sodium matrix. The composite electrode material may be configured to enable sodium extraction primarily from bulk regions rather than being limited to interfacial areas.

[0096] The method may further comprise configuring the composite electrode material to enhance interfacial stability with a NASICON solid electrolyte. This configuration may result from the modified grain boundary structure created by the distributed antimony telluride particles within the sodium matrix. The composite electrode material may be configured to Princeton - 104976 maintain stable contact with the NASICON solid electrolyte during repeated electrochemical cycling operations.

[0097] The manufacturing method may produce a composite electrode material that exhibits the self-healing mechanism wherein sodium may be re-plated into areas where pores have formed during stripping. The distributed antimony telluride particles may enable this re-plating behavior by acting as nucleation regulators and current distributors within the composite structure.

[0098] The holding and folding steps may be performed under controlled conditions to maintain the desired properties of both the sodium matrix and the antimony telluride particles. The number of holding and folding cycles may be optimized to achieve the target level of particle distribution while avoiding excessive processing that could degrade the material properties.

[0099] The composite electrode material produced by this manufacturing method may exhibit enhanced cycling stability and reduced interfacial resistance growth compared to conventional electrode materials. The manufacturing process may be scalable for commercial production while maintaining the uniform distribution and electrochemical properties that contribute to the enhanced battery performance.

[0100] Referring to FIGS. 2A-2C, experimental cycling tests demonstrate the performance characteristics of the electrode comprising the sodium matrix and antimony telluride particles under various operational conditions. The cycling tests may be performed at a constant current density with stepwise increases in areal capacity, showing consistent low overpotential throughout extended cycling periods.

[0101] As shown in FIG. 2A, the electrode may exhibit stable voltage oscillation behavior when cycled at 0.5 mA / cm2with 0.50 mAh / cm2capacity over approximately 100 hours. The voltage may oscillate in a regular periodic pattern between approximately +0.05 V and -0.05 V throughout the cycling duration. The consistent amplitude and frequency of the voltage oscillations may indicate stable electrochemical behavior during repeated charge and discharge cycles, demonstrating that the antimony telluride particles distributed throughout the sodium matrix maintain their current distribution and nucleation regulation properties over extended operation.

[0102] With reference to FIG. 2B, the electrode may demonstrate continued stable performance when cycled at 0.5 mA / cm2with increased areal capacity of 1.0 mAh / cm2over approximately 100 hours. The voltage may oscillate in a regular periodic pattern between approximately +0.05 V and -0.1 V, with the waveform exhibiting a square- wave-like profile. Princeton - 104976

[0103] The consistent amplitude throughout the extended cycling period may indicate that the bulk stripping mechanism enabled by the antimony telluride particles remains effective at higher areal capacities, allowing for deeper sodium extraction and re-plating without degradation of the electrode performance.

[0104] As further shown in FIG. 2C, the electrode may maintain stable cycling behavior when operated at 0.5 mA / cm2with further increased areal capacity of 2.0 mAh / cm2over approximately 100 hours. The voltage may oscillate in a regular periodic pattern between approximately +0.07 V and -0.1 V, with the waveform displaying a square-wave profile characterized by longer cycle periods compared to the lower capacity cycling conditions. The stable voltage plateaus during both charging and discharging phases may demonstrate that the sodium matrix and antimony telluride particles can accommodate higher capacity cycling while maintaining the self-healing mechanism wherein sodium is re-plated into areas where pores have formed during stripping.

[0105] Referring to FIG. 3A, voltage profile analysis may reveal the electrochemical behavior of the electrode during extended stripping operations at 2.5 MPa pressure conditions. The voltage profile may show an initial value of approximately 0.032 V at the start of the measurement, followed by a gradual increase to about 0.04 V during the first four hours. Between approximately 4 and 7 hours, the voltage may increase more steeply, reaching approximately 0.065 V. After 7 hours, the rate of voltage increase may diminish, and the voltage may continue to rise gradually, reaching approximately 0.075 V by 14 hours. This voltage behavior may indicate a two-step process wherein the antimony telluride particles facilitate controlled sodium extraction from different regions within the electrode structure.

[0106] As shown in FIG. 3B, impedance spectra analysis may demonstrate the interfacial characteristics of the electrode during cycling at 2.5 MPa pressure conditions. The Nyquist plot may display multiple semicircular arcs that begin near the origin and extend across the plot, with the largest semicircle reaching a maximum -Im(Z) value of approximately 20 O. cm at an Im(Z) value of approximately 60 cm. Additional smaller semicircular features may be visible in the mid-frequency region, indicating different electrochemical processes occurring within the electrode structure. The overlapping nature of the impedance curves may suggest minimal interfacial changes during the stripping process, demonstrating that the antimony telluride particles maintain interfacial stability with the solid electrolyte throughout the cycling operation.

[0107] With reference to FIG. 4A, voltage profile analysis at increased pressure conditions of 5 MPa may show continued stable performance of the electrode. The voltage profile may Princeton - 104976 display an initial voltage of approximately 0.018 V that gradually increases over time, with a relatively flat region from 0 to approximately 4 hours, followed by a steeper increase from approximately 4 to 8 hours, and then a more gradual increase from approximately 8 to 12 hours, reaching a final voltage of approximately 0.043 V. The lower overall voltage values compared to the 2.5 MPa conditions may indicate that the increased pressure facilitates more efficient sodium stripping from the bulk portion of the electrode, potentially due to enhanced mechanical contact between the sodium matrix and the antimony telluride particles.

[0108] As further shown in FIG. 4B, impedance spectra analysis at 5 MPa pressure conditions may demonstrate continued interfacial stability of the electrode. The Nyquist plot may show multiple overlapping semicircular curves that form a characteristic impedance pattern, with the curves starting near the origin and extending across the real axis. The data points may form a series of arcs that indicate changes in impedance behavior over the course of the measurement. The relatively stable interfacial characteristics, as indicated by the overlapping nature of the curves, may demonstrate that the electrode maintains consistent electrochemical properties and interfacial contact with the solid electrolyte under the higher pressure conditions.

[0109] The experimental results may demonstrate that the electrode comprising the sodium matrix and antimony telluride particles achieves consistent electrochemical performance across different areal capacities and pressure conditions. The voltage profiles may show controlled and predictable behavior during sodium stripping operations, while the impedance spectra may indicate minimal interfacial degradation throughout the cycling process. These performance characteristics may result from the bulk stripping mechanism enabled by the antimony telluride particles, which may facilitate uniform sodium extraction and re-plating while maintaining structural integrity of the electrode and stable contact with the solid electrolyte.

[0110] There are several technical advantages of the sodium antimony telluride electrode material of the present disclosure. First, the bulk stripping mechanism enabled by the distributed antimony telluride particles represents a fundamental advancement over conventional electrode materials that are limited to interfacial sodium extraction. This bulk stripping capability allows for more complete utilization of the electrode material and enhanced capacity retention during cycling. Additionally, the self-healing mechanism wherein sodium is re-plated into areas where pores have formed during stripping provides exceptional cycling stability by preventing the accumulation of voids that ty pically degrade electrode performance over time. The enhanced interfacial stability with NASICON solid electrolytes eliminates the safety’ concerns and performance limitations associated with liquid electrolyte systems, enabling the development of safer and more reliable solid-state batteries. Furthermore, the Princeton - 104976 electro-chemo-mechanical grain-boundary stabilization process achieved through microstructural regulation of the sodium host lattice provides superior mechanical contact preservation compared to conventional wetting-controlled mechanisms. The uniform current distribution and nucleation regulation properties of the embedded antimony telluride particles promote consistent electrochemical behavior across the entire electrode, reducing localized stress concentrations and extending battery lifespan. The scalable fabrication process involving grinding and controlled distribution techniques allows for commercial production while maintaining the uniform particle distribution essential for optimal performance. These technical advantages collectively contribute to a transformative electrode material that addresses critical limitations in solid-state sodium battery technology while providing enhanced safety, performance, and manufacturing scalability.

[0111] A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the disclosure. Accordingly, other implementations are within the scope of the following claims.

Claims

Princeton - 104976CLAIMS1. A composition of matter, comprising: a sodium matrix; and a plurality of antimony telluride particles distributed throughout the sodium matrix, wherein the composition of matter is configured to facilitate sodium stripping from a bulk portion of the composition of matter during electrochemical cycling.

2. The composition of matter of claim 1, wherein the plurality of antimony telluride particles are substantially evenly distributed throughout the sodium matrix.

3. The composition of matter of claim 1, wherein the plurality of antimony telluride particles have an average particle size of less than 10 pm.

4. The composition of matter of claim 3, wherein the plurality of antimony telluride particles have an average particle size of less than 5 pm.

5. The composition of matter of claim 1, wherein the antimony telluride particles comprise SbzTea.

6. The composition of matter of claim 1, wherein the composition of matter is configured to facilitate sodium re-plating into areas where pores have formed during stripping.

7. The composition of matter of claims 1-6, wherein the composition of matter is configured to enhance interfacial stability with aNASICON solid electrolyte.

8. The composition of matter of claim 7, wherein the NASICON solid electrolyte comprises NasZr2Si2POi2.

9. A solid-state battery, comprising: a solid electrolyte; and an electrode comprising a sodium matrix and a plurality of antimony telluride particles distributed throughout the sodium matrix, wherein the electrode is configured to maintain interfacial stability with the solid electrolyte during electrochemical cycling by facilitating sodium stripping from a bulk portion of the electrode.

10. The solid-state battery of claim 9, wherein the solid electrolyte comprises a NASICON material.

11. The solid-state battery of claim 10, wherein the NASICON matenal comprises Na3Zr2Si2POi2.

12. The solid-state battery of claim 9, wherein the plurality of antimony telluride particles are substantially evenly distributed throughout the sodium matrix.

13. The solid-state battery of claim 9, wherein the plurality of antimony telluride particles have an average particle size of less than 10 pm.Princeton - 10497614. The solid-state battery' of claims 9-13, wherein the electrode is configured to facilitate sodium re-plating into areas where pores have formed during stripping.

15. The solid-state battery of claim 9, wherein the electrode comprises an anode.

16. A method of operating a solid-state battery, comprising: providing a solid-state battery7comprising a solid electrolyte and an electrode, wherein the electrode comprises a sodium matrix and a plurality of antimony telluride particles distributed throughout the sodium matrix; applying an electrical potential to the electrode to initiate sodium stripping from a bulk portion of the electrode; and facilitating sodium re-plating into areas where pores have formed during the stripping.

17. The method of claim 16. wherein the solid electrolyte comprises a NASICON material.

18. The method of claim 17, wherein the NASICON material comprises Na3Zr2Si2POi2.

19. The method of claim 16, wherein the plurality of antimony telluride particles have an average particle size of less than 10 gm.

20. The method of claim 16, wherein the antimony telluride particles comprise Sb2Te3.

21. The method of claim 16, further comprising maintaining interfacial stability between the electrode and the solid electrolyte during electrochemical cycling.

22. A method of manufacturing an electrode for a solid-state battery7, comprising: providing a sodium matrix; distributing a plurality of antimony telluride particles throughout the sodium matrix to form a composite electrode material; and configuring the composite electrode material to facilitate sodium stripping from a bulk portion of the composite electrode material during electrochemical cycling.

23. The method of claim 22, wherein distributing the plurality of antimony telluride particles comprises substantially evenly distributing the particles throughout the sodium matrix.

24. The method of claim 22, wherein the plurality of antimony telluride particles have an average particle size of less than 10 gm.

25. The method of claim 22, wherein the antimony telluride particles comprise Sb2Te3.

26. The method of claim 22, further comprising configuring the composite electrode material to enhance interfacial stability with a NASICON solid electrolyte.

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