Sodium-ion battery systems for electric vehicles present unique electrochemical challenges compared to their lithium-ion counterparts. Current sodium-ion cells demonstrate energy densities of 350 Wh/kg in laboratory settings, with practical implementations ranging from 120-160 Wh/kg in modular configurations. The ionic radius of Na+ (102 pm) versus Li+ (76 pm) fundamentally alters intercalation dynamics, requiring electrode materials and cell architectures specifically engineered for sodium's electrochemical properties.

The fundamental challenge lies in balancing sodium's abundant resource advantages against its inherently lower energy density while maintaining the cycle life and thermal stability required for automotive applications.

This page brings together solutions from recent research—including dual-ion positive electrode designs, composite electrode assemblies combining sodium-ion and lithium-ion chemistries, negative electrodes with separate sodium storage and conductive skeleton layers, and modular battery systems with independent cell replacement capabilities. These and other approaches demonstrate how sodium-ion chemistry can be optimized for electric vehicles through material science innovations that address both performance and practical implementation requirements.

1. Battery Cell with Composite Electrode Assembly of Sodium-Ion and Lithium-Ion Electrodes and Variable Charge Capacity Configuration

EVE POWER CO LTD, 2024

A battery cell combining sodium-ion and lithium-ion electrodes in a single cell structure. The cell comprises a composite electrode assembly comprising a sodium-ion positive electrode sheet, a lithium-ion positive electrode sheet, and a separator. The electrodes are arranged in a specific pattern to achieve optimal performance characteristics. The cell features a diaphragm separating the electrodes, with the negative electrode comprising a sodium-ion active material and the positive electrode comprising a lithium-ion active material. The cell can be configured to operate at various charge levels (0.005 to 200 times C), offering enhanced performance compared to traditional battery pack configurations.

WO2024239459A1-patent-drawing

2. Negative Electrode Comprising Sodium Metal Oxide for Enhanced Energy Density in Sodium Ion Batteries

JIANGSU ZOOLNASM ENERGY TECHNOLOGY CO LTD, 2024

Sodium ion batteries achieve higher energy density through novel negative electrode materials. The invention introduces a negative electrode comprising a sodium metal oxide, where the metal oxide is specifically designed to enhance the negative electrode's performance while maintaining safety. This material combines the benefits of sodium metal with the advantages of oxide materials, enabling significant improvements in energy density compared to conventional negative electrodes.

CN118472352A-patent-drawing

3. Sodium Ion Battery with Negative Electrode Featuring Separate Sodium Storage and Conductive Skeleton Layers

XIAMEN HAICHEN ENERGY STORAGE TECH CO LTD, 2024

Sodium ion battery design with improved cycle life and energy density for sodium ion batteries used in energy storage applications. The design involves a specialized negative electrode structure with a separate sodium storage layer and conductive skeleton layer. The sodium storage layer provides the sodium intercalation capacity, while the conductive skeleton layer promotes uniform sodium deposition and prevents dendrite growth. The capacity ratio of the sodium storage layer to the positive electrode layer is controlled to optimize energy density and cycle life.

CN117810523A-patent-drawing

4. Sodium-Ion Battery Cathode Material with NaFePO4 and NaFeP2O7 Composite and Specific Particle Size Distribution

NINGDE CONTEMPORARY AMPEREX TECH CO LTD, 2023

A sodium-ion battery cathode material comprising a positive electrode active material comprising a combination of NaFePO4 and NaFeP2O7, with particle size distribution of 3-8.5 μm. The material combines the high capacity and rate performance of NaFePO4 with the improved stability and mechanical properties of NaFeP2O7.

5. Hybrid Battery Pack with Series-Connected Lithium-Ion Cells and Parallel-Connected Sodium-Ion Cells

SINOTRUK JINAN POWER CO LTD, 2023

Hybrid battery pack that combines the high energy density of lithium-ion cells with the low cost and high temperature performance of sodium-ion cells. The pack features an array structure comprising both types of cells, where the lithium-ion cells are connected in series and the sodium-ion cells are connected in parallel. This arrangement enables the lithium-ion cells to maintain their high charge and discharge capacity even at extreme temperatures, while the sodium-ion cells provide their unique benefits of high thermal stability and rapid charging capabilities. The pack's architecture allows the lithium-ion cells to be directly connected to the sodium-ion cells, eliminating the thermal management challenges typically associated with lithium-ion battery pack assembly.

CN116093526A-patent-drawing

6. Flexible Sodium-Ion Battery Negative Electrode with In-Situ Grown Nickel Sulfide on Carbon Nanotube Film

CHUNENG NEW ENERGY CO LTD, 2023

Flexible sodium-ion battery negative electrode comprising carbon nanotube film as current collector, and nickel sulfide negative electrode material grown on the carbon nanotube film in-situ. The negative electrode achieves high performance through the unique combination of carbon nanotube film's high surface area and excellent mechanical properties, while the nickel sulfide material's high sodium storage capacity and mechanical stability enable reliable performance across repeated bending cycles.

7. Sodium-Ion Battery Positive Plate with Controlled Binder Distribution for Enhanced Conductivity

ZHEJIANG GEELY POWER ASSEMBLY CO LTD, 2022

Sodium-ion battery positive plate with enhanced electrical conductivity through optimized binder distribution. The plate comprises a positive current collector with a surface featuring a specific binder concentration, and a positive active material arranged on this surface. The binder concentration is precisely controlled to achieve optimal conductivity while maintaining the positive electrode's non-oxidizable nature. The negative electrode current collector also features a controlled binder concentration, with both foil and rubber emulsion options available. This configuration enables the positive plate to achieve high electrical conductivity while maintaining the negative electrode's safety characteristics.

8. Polyanionic Sodium-Ion Battery Cathode Material with Liquid-Phase Metal Phosphate Composition Control

SHENZHEN JIANA ENERGY TECH CO LTD, 2022

Polyanionic sodium-ion battery cathode material with improved performance and scalability. The material is a single-phase or two-phase sodium ion battery cathode made from a novel liquid-phase preparation method that enables precise control of metal phosphate composition through citric acid complexation. The method ensures uniform distribution of metal ions during solution preparation, eliminating common issues associated with traditional solid-phase ball milling. The resulting material exhibits excellent electrochemical performance, stability, and reproducibility, making it suitable for large-scale production.

9. Sodium-Ion Battery with Hard Carbon Negative Electrode for Sodium Metal Cluster Formation

GUO MINQI, 2022

Sodium-ion battery with improved energy density through the use of high-density sodium metal clusters as negative electrodes. The battery employs a novel negative electrode material, specifically hard carbon, which enables the formation of sodium metal clusters through controlled intercalation. This material's unique properties, including its high true density and extensive sodium intercalation void space, allow for efficient sodium ion storage and release. The battery design combines the hard carbon material with a conductive agent and binder to create a robust and efficient negative electrode system.

10. Battery with Perforated Negative Electrode Current Collector for Controlled Ion Intercalation

ZHUHAI GUANYU POWER BATTERY CO LTD, 2022

Battery with enhanced power density through improved electrode interface properties. The battery comprises a positive electrode sheet, a negative electrode sheet, and a separator. The positive electrode sheet contains a positive electrode current collector and a positive electrode coating, while the negative electrode sheet includes a negative electrode current collector and a negative electrode coating. The negative electrode current collector features a network of holes with diameters ranging from 50 to 400 micrometers and spacings of 0.5 to 1 millimeter. This unique electrode architecture enables controlled lithium ion intercalation and transfer while maintaining high power density.

CN115101737A-patent-drawing

11. Sodium Ion Doped Mixed Sodium Iron Pyrophosphate Cathode with In-situ Carbon Coating

SHANGHAI UNIVERSITY OF ELECTRIC POWER, 2022

Trivalent sodium ion doping of mixed sodium iron pyrophosphate cathode materials for sodium-ion batteries, where the doping replaces divalent iron ions. The material combines trivalent sodium-doped mixed sodium iron pyrophosphate with in-situ carbon coating, resulting in a material with enhanced conductivity and surface properties.

CN114759173A-patent-drawing

12. Mixed Crystal Polyanionic Phosphate Cathode with Micro- and Nanostructured Porosity for Sodium-Ion Batteries

UNIV FUDAN, 2021

A mixed crystal polyanionic phosphate cathode material for sodium-ion batteries with enhanced electrochemical performance. The material comprises sodium iron phosphate, sodium iron pyrophosphate, and sodium iron phosphate with micro- and nanostructured macropores and mesopores, achieving high specific capacity and long cycle life. The material's unique microstructure enables efficient sodium ion migration through its porous network, while maintaining structural integrity.

CN113675390A-patent-drawing

13. Aqueous Sodium-Based Mixed Ion Secondary Battery with Layered Sodium Manganate Anode and Metal Oxide Cathode

ENPOWER ENERGY TECH NANTONG CO LTD, 2021

Aqueous sodium-based mixed ion secondary battery that achieves higher energy density and better cycle performance compared to traditional single-ion batteries. The battery employs a layered structure with sodium manganate as the anode material, where sodium ions intercalate and desorb through layered intercalation and deposition reactions. The negative electrode is composed of a metal oxide, with additional conductive carbon and binder materials. The electrolyte is a saturated metal oxide solution in a sodium hydroxide solution. The battery's unique design enables simultaneous ion storage and release through the layered structure, resulting in improved performance characteristics.

WO2021208299A1-patent-drawing

14. Iron-Based Polyanionic Compound Electrode Material with Graphene Surface Integration

SHANGHAI UNIVERSITY OF ELECTRIC POWER, 2021

Modified iron-based polyanionic compound positive electrode material for sodium-ion batteries, comprising graphene supported on the surface of the modified iron-based polyanionic compound. The material combines the high electronic conductivity and reversible discharge capacity of iron-based polyanions with the enhanced mechanical stability and surface area of graphene. The material achieves improved performance in sodium-ion batteries through its optimized surface structure.

15. Sodium-Ion Battery with Sodium-Based Cathode Incorporating Sodium Perchlorate for Enhanced Storage Capacity and Cycle Stability

GUILIN UNIVERSITY OF ELECTRONIC TECHNOLOGY, 2021

A sodium-ion battery design that addresses the limitations of current lithium-ion batteries through the use of a sodium-based cathode material. The battery combines the advantages of both lithium-ion and sodium-ion batteries, featuring a sodium-based cathode that achieves high storage capacity while maintaining excellent cycle stability. The cathode material, comprising sodium and sodium perchlorate, provides a unique combination of high sodium storage capacity and reversible electrode properties. This design enables the creation of a hybrid battery that can replace lithium-ion batteries while overcoming the challenges associated with sodium-ion batteries.

16. Sodium Ion Battery with Uniform Negative Electrode Layer Comprising Disordered Carbon Materials

FARADION LTD, 2021

Sodium ion battery with enhanced capacity and cycle life, achieved through a uniform negative electrode active material layer containing disordered carbon materials. The battery features a cathode comprising positive electrode materials with a uniform positive electrode active material layer, and an anode comprising a negative electrode active material layer on a substrate. The negative electrode layer contains disordered carbon materials, which provide improved capacity retention and cycle stability compared to conventional uniform carbon layers. The battery architecture enables higher capacity and improved cycle life compared to conventional designs, particularly at high charge rates.

CN113196526A-patent-drawing

17. Sodium-Based Electrolyte System with Enhanced Ion Mobility for Sodium-Ion Batteries

NINGDE CONTEMPORARY AMPEREX TECHNOLOGY CO LTD, 2020

Sodium-ion battery technology offers a promising alternative to lithium-ion batteries due to its abundant sodium resources and lower cost. However, current sodium-ion batteries face significant challenges in achieving high first-time Coulombic efficiency and rate performance. A new generation of sodium-ion batteries addresses these limitations through the development of a sodium-based electrolyte system. The system enables improved performance characteristics, including enhanced first-time Coulombic efficiency and rate capability, through the use of a novel electrolyte composition that optimizes sodium ion mobility and charge transport.

18. Method for Synthesizing Sodium-Ion Battery Cathode Materials via V Ion Substitution with Cr and Mn in Na3V2(PO4)3 Structure

GUILIN UNIVERSITY OF TECHNOLOGY, 2020

A method for preparing and utilizing sodium-ion battery cathode materials through substitution of V ions with Cr and Mn ions in the Na3V2(PO4)3 structure. The preparation involves replacing V ions with Cr and Mn ions to form Na4CrMn(PO4)3 while maintaining the original crystal structure and electrical neutrality. This substitution enables the material to exhibit higher theoretical capacity densities compared to conventional Na3V2(PO4)3. The resulting material retains the unique three-dimensional framework of the original material, making it suitable for sodium-ion battery applications.

19. Crystalline Sodium Cobalt Pyrophosphate Composition for Sodium-Ion Battery Electrodes

NIPPON ELECTRIC GLASS CO LTD, 2019

Positive electrode active material for sodium-ion batteries that achieves high voltage and capacity through a novel crystal structure containing cobalt. The material consists of crystalline Na3Co2P2O7, Na3Co2I8P2O7, and Na5Co4P8O28, with specific particle sizes and crystal structures optimized for efficient sodium ion conduction and mechanical integrity. The material's unique crystal structure enables high discharge voltages without compromising capacity, making it suitable for portable electronic devices, electric vehicles, and other applications requiring high-voltage batteries.

20. Sodium-Ion Battery Positive Electrode Material with Divalent Metal Ion-Infused Glass Matrix

NIPPON ELECTRIC GLASS CO, 2019

Positive electrode material for sodium-ion batteries with enhanced voltage and capacity, comprising a glass matrix containing divalent iron, cobalt, chromium, manganese, and nickel, along with sodium ions, which can be crystallized through controlled firing processes. The material combines the benefits of divalent metal ions to enhance charge storage while maintaining high discharge capacity, with the glass matrix providing mechanical strength and thermal stability. The material's composition and crystallization conditions are optimized to prevent oxidation and decomposition of the iron and cobalt components during the firing process, resulting in a stable and reliable electrode for high-voltage sodium-ion batteries.

21. Sodium Vanadium Phosphate Composite with Carbon Coating for Battery Electrodes

22. Sodium Ion Battery Electrolyte with Hydrated Glass Matrix and External Sodium Salt Component

23. Sodium-Ion Battery Positive Electrode Material with Nickel-Based Transition Metal Composition and Controlled Crystalline-Amorphous Phases

24. Sodium-Ion Battery with Mass-Balanced Negative and Positive Electrodes for Voltage Stability

25. β-Alumina-Based Solid Electrolyte with Controlled Thickness and Porosity for Sodium-Ion Conductivity

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