A versatile reactive layer toward ultra-long lifespan lithium metal anodes

Unstable anode/electrolyte interfaces have significantly hindered the development of lithium (Li) metal batteries under high rates and large capacities. In this study, a versatile reactive layer based on sulfur-selenium crosslinked polyacrylonitrile brushes has been developed by a combined strategy of polymer topology design and chemical crosslinking. The sulfur-selenium crosslinked polyacrylonitrile side-chains can react with Li to generate passivated Li₂S-Li₂Se-containing solid electrolyte interphase while 3D lithiophilic porous nanonetworks enable Li penetration, contributing to achieving rapid and uniform Li ion flux and a dendrite-free anode. With these merits, ultralong-term stable cycling (over 1 year and 4 months) at a high current density of 10 mA cm^-2 has been achieved for the protected Li anodes. Moreover, even when tested in high-loading Li|NCM622 cell (21.6 mg cm^-2) and Li-S cell with a low negative to positive electrode capacity ratio (1.4), stable cycling performances can also be achieved.