High-Voltage Cathode Materials for Sodium-Ion Batteries: Advances and Challenges.

Sodium-ion batteries (SIBs) gain attention as a promising, cost-effective, and resource-abundant alternative, especially for large-scale energy storage. Cathode materials play a pivotal role in improving the electrochemical performance of SIBs, with high-voltage cathodes providing enhanced energy density and rate capacity, making SIBs suitable for high-power applications. Common cathode materials, such as layered transition metal oxides, polyanionic compounds, and Prussian blue analogs, each offer unique benefits. However, these materials face challenges under high-voltage conditions, such as phase transitions, metal cation migration, oxygen loss, and electrolyte degradation. This review discusses strategies to address these challenges, including elemental doping, surface coatings, modified synthesis methods, and interfacial adjustments, all aimed at enhancing the stability and electrochemical performance of high-voltage cathode materials. Here also explores how full-cell design optimizations can further improve energy and power density. By analyzing material degradation and failure modes, this review offers insights into the development of stable, high-performance SIBs with better safety and broader application potential in energy storage technologies.