Recent Progress of Covalent Organic Framework Materials for Anodes Protection in Sodium Metal Batteries

Sodium (Na) metal batteries, using Na metal as anode, have emerged as a new kind of promising battery technologies owing to their advantages of rich Na resources, high energy density and high safety. However, Na metal anodes also face challenges such as uncontrollable Na dendrite growth, generation of “dead Na”, and instability of the electrolyte-electrode interphase, which restrict the performance of Na metal batteries. To solve these problems, one of efficient strategies is to develop a stable interface layer, which has attracted tremendous attention. Among various designed materials, covalent organic frameworks (COFs), as a type of crystalline porous materials connected by covalent bonds, in separator modification, quasi-solid electrolyte construction, and Na anode design, it has initially shown great potential in Na metal anode protection due to their adjustable pore structure, high specific surface area and modifiable skeleton. This article reviews the research progress of COFs for the anode protection in Na metal batteries over recent years, provides an outlook on future challenges and application prospects, and offers new avenues for the design and functional development of new-type COFs and the application of energy storage devices.