Single Crystal Layered Transition Metal Oxide Cathode Materials for Sodium-Ion Batteries: Potential and Progress

Abstract

With the growing demand for high-energy-density secondary batteries, layered oxide cathode materials with high specific capacity, such as Na_XMO₂, have emerged as a prominent category among sodium-ion battery cathode materials. Among these, single-crystal layered oxide cathode materials demonstrate enhanced mechanical stability and safety, improving the overall battery performance. This review systematically summarizes recent advances in single-crystal layered oxide cathodes for sodium-ion batteries. It delineates the primary synthesis methods employed for these materials, including high-temperature solid-state method, molten-assisted synthesis, and hydrothermal/solvothermal method, and analyzes the advantages and limitations of each approach. Furthermore, this review summarizes modification strategies such as elemental doping and surface coating, and highlights their impacts on the electrochemical performance and critical operational parameters of single-crystalline oxide cathodes. The analysis can provide valuable guidance for developing and implementing sodium-ion battery technologies.