Coupling 3D vertical graphene skeleton with lithophilic ZnO Interface to enable highly stable lithium metal anode

Abstract

Lithium metal has been considered as the most promising anode material for high energy density batteries owing to its high theoretical capacity and low reduction potential. Unfortunately, the uncontrollable growth of lithium dendrites and unrestrained volume expansion seriously hinder its practical applications. Designing 3D skeletons with high electronic conductivity, and superior lithophilicity to control the lithium plating/stripping process has been proven to be an effective strategy to alleviate these two issues. In this study, ZnO-decorated 3D vertical graphene skeleton (ZnO@VG) was developed as the host material to regulate lithium nucleation and dendrite growth. Attributing to the unique cavity arrangement, enlarged specific surface area, and numerous lithiophilic sites of ZnO@VG, a remarkable coulombic efficiency of 99.12 % after 350 cycles is achieved. Furthermore, symmetric cells based on ZnO@VG/Li electrodes demonstrate lower voltage polarization and enhanced cycling stability (over 1800 h) at 0.5 mA cm−2 and 1 mA h cm−2. Notably, when coupled with a LiFePO4 cathode, the full cell exhibits a discharge specific capacity of 100.33 mA h cm−2 at 5 C and maintains a high capacity retention of 89.1 % after 740 cycles at 1 C.