Research Progress of Sodium-Ion Cathode Materials

Abstract

Sodium-ion batteries have attracted extensive attentions as a promising alternative to lithium-ion batteries due to the abundant natural resources of sodium and the expected low production cost. This paper presents a detailed review on recent advances of sodium-ion battery cathode materials, which are considered as the most important part contributing to the overall performance of a battery. According to structural features, electrochemical behavior, advantages and disadvantages, sodium-based polyanionic compounds, Prussian blue analogues and layered transition metal oxides as cathode materials are reviewed in this article. Moreover, different from lithium-ion battery, much bigger ionic radius of sodium ion results in much more complicated working mechanism. The technical challenges of sodium-ion batteries including low energy density, poor cycling stability and limited rate capability are analyzed in details. The strategies to solve above problems are discussed in details. These strategies include elemental doping, surface coating, nano-structuring and novel structural engineering strategies including highentropy stabilization. The emerging research trends and future development directions are identified based on materials development, structure optimization, cost reduction and environment friendliness. The conventional idea is summarized and detailed discussions are offered to guide the further advance of high-performance sodium-ion batteries towards commercialization.