Advanced nanoengineering strategies endow high-performance layered transition-metal oxide cathodes for sodium-ion batteries

Considering the abundance and low price of sodium, sodium-ion batteries (SIBs) have shown great potential as an alternative to existing lithium-based batteries in large-scale energy storage systems, including electric automobiles and smart grids. Cathode materials, which largely decide the cost and the electrochemical performance of the full SIBs, have been extensively studied. Among the reported cathodes, layered transition-metal oxides (LTMOs) are regarded as the most extremely promising candidates for the commercial application of the SIBs owing to their high specific capacity, superior redox potential, and suitable scalable preparation. Nevertheless, irreversible structural evolution, sluggish kinetics, and water sensitivity are still the critical bottlenecks for their practical utilization. Nanoengineering may offer an opportunity to address the above issues by increasing reactivity, shortening diffusion pathways, and strengthening structural stability. Herein, a comprehensive summary of the modification strategies for LTMOs is presented, emphasizing optimizing the structure, restraining detrimental phase transition, and promoting diffusion kinetics. This review intends to facilitate an in-depth understanding of structure-composition-property correlation and offer guidance to the further development of the LTMO cathodes for next-generation energy storage systems.