Advancing high-voltage cathodes for sodium-ion batteries: Challenges, material innovations and future directions

Abstract

High-voltage cathode materials are fundamental to the advancement of sodium-ion batteries (SIBs), offering a sustainable and cost-effective alternative to lithium-ion batteries for energy storage. This review comprehensively examines critical cathode material classes, including polyanionic compounds, layered transition metal oxides, tunnel-structured materials, and Prussian blue analogues. These materials exhibit diverse structural and electrochemical properties, addressing specific challenges such as phase transitions, low conductivity, and structural instability. To overcome these issues, innovative strategies including doping, gradient structures, surface engineering, nano-structuring, and high-entropy material design are developed, offering pathways to enhance stability and capacity retention under high-voltage conditions. Furthermore, advanced characterization techniques and artificial intelligence-driven tools are explored to provide deeper insights into the behaviors of cathode materials, enabling real-time structural analysis and predictive computational modeling for optimization. Integrating experimental and computational approaches not only accelerates the discovery of next-generation cathode materials but also addresses the trade-offs between performance, scalability, and sustainability. By offering a comprehensive framework, this review identifies critical directions for overcoming existing challenges and unlocking the full potential of high-voltage cathode materials for SIBs in grid-scale energy storage and renewable energy applications.