Mn-based tunnel-structured Na0.44MnO2 cathode materials for high-performance sodium-ion batteries: electrochemical mechanism, synthesis and modifications

Sodium-ion batteries (SIBs) have emerged as promising and mature alternatives to lithium-ion batteries (LIBs) in the post-LIB era, necessitating the development of cost-effective and high-performance cathode materials. The unique crystal texture of Mn-based tunnel-structured cathode materials offers outstanding cycling stability, rate capability and air stability, making them a highly attractive option for sodium-ion storage applications. This comprehensive review summarizes recent advancements in the understanding of sodium-ion storage mechanism, synthesis techniques, and modification strategies for Mn-based tunnel-structured cathode materials, thereby significantly contributing to the advancement of high-performance cathodes for SIBs.