Two-dimensional matrices confining metal single atoms with enhanced electrochemical reaction kinetics for energy storage applications

Abstract

Diversified electrochemical energy storage systems highly depend on electrode material construction. In this area, single-atom catalysts intentionally incorporated within two-dimensional (2D) matrices (SAs@2D) can offer desirable advantages derived from host–guest interactions with abundant extrinsic defects. Nevertheless, the intrinsic manipulation mechanisms and guiding insights regarding the use of SAs@2D in various energy storage devices have not been comprehensively appraised. Firstly, newly updated synthesis methodologies and structure–activity mechanisms are summarized in this review. Then, cutting-edge applications regarding the use of SAs@2D hybrids in various rechargeable batteries, such as Li–O₂, Li–CO₂, Li–S, Li–metal, and Zn–air batteries, and the central kinetics amelioration schemes underlying these applications are highlighted in detail for the first time. We argue that the maximally exposed active centers and optimized electronic environments are responsible for enhancing mass transfer throughout the conductive grid, which is indispensable for accelerating the redox kinetics and enhancing energy efficiencies in advanced battery systems. In particular, in-depth mechanisms describing how high-density unsaturated coordination sites can tune the adsorption-nucleation-growth behaviors of intermediates in the framework and how the impressive electronic and structural characteristics of SAs@2D can lower potential energy barriers during redox reactions are fundamentally concentrated on. Finally, challenges and advisory guidelines for further investigations relating to the use of SAs@2D in rechargeable batteries are presented.