Highly stable Li+ deposition guided by a lithiophilic microchannel

Abstract

The repeated volume variation of lithium (Li) metal anode (LMA) upon Li⁺ plating/stripping, the volatile interface between Li and the electrolyte, and the incessant growth of Li dendrites on Li metal surface have severely hindered the practical application of Li in constructing high energy-density Li metal batteries (LMBs). Herein, a novel Li host (3D ZnO/CNTs/Cu) featuring ordered microchannels and lithiophilic ZnO species on the inner walls of the microchannels is introduced, which induces the uniform Li⁺ deposition into the microchannels and finally suppresses the formation of Li dendrites. The stable structure of the fabricated 3D Li host can adapt to volume variations upon Li⁺ plating/stripping, thereby enhancing electrochemical performances. Symmetric cells with the 3D ZnO/CNTs/Cu@Li anode exhibited long cycle stability at areal current densities of 0.5 and 2 mA cm⁻²; Full cells maintained a reversible discharge capacity of 105 mAh g⁻¹ after 400 cycles at 1C with a capacity retention of 70%. Meanwhile, ex-situ SEM observations proved that the 3D ZnO/CNTs/Cu@Li anode can keep the structural integrity during charging/discharging (or plating/stripping). This work suggested that lithiophilic nanochannels in the Li host can significantly improve the electrochemical performance and safety of LMBs.