Free-standing 3D nitrogen–carbon anchored Cu nanorod arrays: in situ derivation from a metal–organic framework and strategy to stabilize lithium metal anodes

Abstract

Lithium (Li)-metal is considered to be the most promising candidate as an anode to design higher energy density lithium batteries because of its extremely high specific capacity (3860 mA h g⁻¹) and lowest redox potential (−3.04 V vs. SHE). However, the safety concerns of lithium dendrites, low coulombic efficiency, and infinite volume variation remain challenging for practical applications. Herein, a free-standing 3D nitrogen–carbon anchored Cu nanorod array (NC/Cu) as a new current collector is introduced. It was in situ derived from a metal–organic framework (MOF) and could allow the dendrite-free deposition of the lithium metal. Benefiting from the uniqueness of the hetero-atom compositions and the 3D structure, the NC/Cu displayed much lower interfacial resistance and more stable Li plating/stripping behaviors compared to those of the planar Cu foil. A coulombic efficiency higher than 97% and long cycle life over 200 cycles were finely achieved with the specific capacity of 2.0 and 1.0 mA h cm⁻², respectively. The merit of NC/Cu was further demonstrated in the lithium batteries versus the LiFePO₄ cathode, where the cycle ability and electrochemical performances were significantly boosted. This study opens a new avenue to stabilize lithium metal anodes from the unique derivations of MOFs and more relevant researches on lithium metal chemistries deserve to be explored.