Energy Storage Mechanism, Challenge and Design Strategies of Metal Sulfides for Rechargeable Sodium/Potassium‐Ion Batteries

Abstract Rechargeable sodium/potassium‐ion batteries (SIBs/PIBs) with abundant reserves of Na/K and low cost have been a promising substitution to commercial lithium‐ion batteries. As for pivotal anode materials, metal sulfides (MSx) exhibit an inspiring potential due to the multitudinous redox storage mechanisms for SIBs/PIBs applications. Nevertheless, they still confront several bottlenecks, such as the low electrical conductivity, poor ionic diffusivity, sluggish interfacial/surface reaction kinetics, and severe volume expansion, which distinctly restrain the battery performance. Meanwhile, the systematic insights into the design strategies of MSx for SIBs/PIBs have been seldom elaborated. In this review, the energy storage mechanism, challenge, and design strategies of MSx for SIBs/PIBs are expounded to address the above predicaments. In particular, design strategies of MSx are highlighted from the aspects of morphology modifications involving 1D/2D/3D configurations, atomic‐level engineering containing heteroatom doping, vacancy creation, and interlayer spacing expansion, and MSx composites with other MSx, metal oxides, carbonaceous, and graphite materials to boost the comprehensive electrochemical performance of SIBs/PIBs. Furthermore, prospects are presented for the further advance of MSx to surmount imminent challenges, hoping to forecast feasible future orientations in this field.