Research Progress in Structure Design and Interface Enhancement of Lithium Anode for High-performance Lithium Metal Batteries

As the most widely used secondary battery at present, lithium-ion batteries (LIBs) with graphite anode cannot meet the increasing demands for high energy density storage systems in consequence of the low theoretical capacity of graphite (372 mAh/g). Among all anode candidates, metallic Li has been regarded as the most promising anode for the next generation rechargeable batteries, due to its ultrahigh theoretical capacity of 3860 mAh/g and its lowest redox potential (-3. 04 V, versus standard hydrogen electrode). Especially, when Li is coupled with high-energy non-Li-containing cathodes such as S and O2, the assembled Li-S and Li-O2 batteries boast a much higher energy density than LIBs, thus deserving to be intensively investigated. However, low Coulombic efficiency and poor stability have been crucial factors limiting the commercial application of lithium metal batte-ries (LMBs). When directly used as the negative electrode, metallic Li is easy to react with electrolytes, forming a chemically unstable and mechanically fragile solid electrolyte interphase (SEI) between them. The repeated rupture of SEI caused by the drastic volume expansion of anode during continuous cycling will induce the dendrites growth and 'dead Li' formation, leading to irreversible capacity loss. Furthermore, when lithium dendrites grow to a certain extent, they will penetrate the separator, resulting in cell shorting or even explosion, thus causing serious safety hazard. Extensive efforts have been devoted to dealing with the issues mentioned above, including failure mechanism exploration, structure design and interface enhancement of lithium metal anode. Some advanced technologies, such as introducing 3D, surface modified current collectors and building in-situ/artificial SEI on lithium anode, are effectively applied to inhibit the dendrite growth and alleviate the volume effect based on the widely accepted theoretical models like Chazalviel-Brissot model, Yamaki model and electrostatic shielding model. This review systematically introduces several typical failure mechanisms of lithium metal anodes and emphatically summarizes the recent key progress in structure design and interface enhancement strategies of lithium metal anode. After analyzing the remaining challenges, some suggestions are also provided to accelerate the commercialization of LMBs. © 2022 Cailiao Daobaoshe/ Materials Review. All rights reserved.