In-situ tailored 3D Li2O@Cu nanowires array enabling stable lithium metal anode with ultra-high coulombic efficiency

Abstract

Suffering from uncontrollable dendrite growth and volume expansion, Li metal batteries have the drawbacks of low coulombic efficiency and short cycle life, which severely limits its practical application. Herein, a multifunctional 3D skeleton of Li2O@Cu composite nanowires array on Cu foam (Li2O@CuNA/CF), in which the Li2O is homogenously distributed onto the Cu nanowires array through the in-situ spontaneous reaction between CuO nanowire and Li metal or electrochemical lithiation of CuO, is designed and serves as lithium storage host for Li metal anode. The lithiophilic Li2O@CuNA provides enough Li nucleation sites for regulating the distribution of Li ions and homogenizing the repeated plating/stripping of Li. The Li2O@CuNA/CF hierarchical structure ensures the rapid charge transfer and inhibits of Li volume expansion. As a result, Li is well accommodated in the Li2O@CuNA/CF skeleton and no distinct Li dendrite is observed. More importantly, the coulombic efficiency is up to 98.5% after 300 cycles in half-cell. The corresponding Li2O@CuNA/CF/Li symmetric cell exhibits superior stable voltage profile with ultra-low voltage hysteresis (15 mV) for 600 h. This work provides a guide for building a 3D Li2O-metal lithiophilic framework for safe and stable Li anode in Li metal batteries.