Cu-CNTs current collector fabricated by deformation-driven metallurgy for anode-free Li metal batteries

Abstract

Rechargeable anode-free Li metal batteries (AFLMBs) with improved energy density and reduced cost are beneficial for emission peak and carbon neutralization. Herein, multi-walled carbon nanotubes reinforced Cu matrix composite (Cu-CNTs) enabled by deformation-driven metallurgy (DDM) technology is proposed to retrieve the lithiophilicity of current collectors (CCs) in AFLMBs. Fine-grained Cu-CNTs with a large number of grain boundaries and homogenous distribution of broken CNTs are achieved based on the severe plastic deformation principle since the CNTs inhibit slide of dislocations and migration of grain boundaries. Grain boundaries in fine-grained Cu-CNTs with low-size distribution gradients provide desirable nucleation sites due to their higher disorder and active state. Excellent lithiophilicity of the broken CNTs is exhibited where its layered structure for Li ion insertion contributes to uniform Li deposition. Half cells assembled by Cu-CNTs CC with 2 vol% CNTs display advanced cycling stability with an average coulombic efficiency of 97.8% after 500 cycles at 1.0 mA‧cm−2. Full cells with LiFePO4 cathode possess excellent capacity retention of 69.4% after 100 cycles at 0.5 C. This work provides a novel strategy for fabricating CCs to achieve superior electrochemical performances for future applications of AFLMBs.