In situ construction of inorganic component-rich polymers as interfacial stabilizers for high-rate lithium metal batteries

Lithium-metal batteries (LMBs) have attracted special interest owing to their high energy densities. Nevertheless, the unfavorable reactivity of lithium metal (Li metal) leads to the uncontrolled growth of dendrites and formation of unstable solid electrolyte interlayers, which shorten the cycle life of Li metal and limit its wide application. Herein, a conformal and thin protective layer, composed of Sn, an Sn–Li alloy, lithium fluoride (LiF), and polyethylene oxide (PEO) (denoted as Li-Sn-LiF@PEO), is constructed in situ on Li metal via a facile one-step method. This conformal artificial layer not only reduced the subsequent surface reactions of lithium with the electrolytes, but also effectively accommodated the large volume change of the Li-metal anode and suppressed the growth of Li dendrites. Symmetric cells with Li-Sn-LiPEO-modified Li-metal anodes exhibited small voltage hysteresis and outstanding plating/stripping cyclability over 400 h at high current densities and capacities of 20 mA cm−2 and 20 mAh cm−2. When coupled with NCA/NCM523/LiFePO4 cathodes, the corresponding LMBs exhibited remarkable cycling life and superior rate properties. These encouraging results demonstrate a novel and promising method for long-life and large-scale stable LMBs.