A Cu-Zn bimetallic organic framework as protective interlayer for dendrite-free Zn deposition in zinc-based flow batteries

Abstract

Zinc-based flow batteries hold great promise for grid-scale energy storage. However, the formation of zinc dendrites challenges their lifespan and safety. In this work, we devise a bimetallic organic framework material on carbon cloth (CuZn@MOF-CC) using a one-step dip coating method to address the dendrite issue. The prepared CuZn@MOF-CC promotes the creation of zincophilic sites on the electrode surface, facilitating smooth and uniform zinc deposition. Electrochemical csharacterizations and density functional theory (DFT) calculations reveal much stronger electronic interactions between CuZn@MOF and the zinc atoms compared to the commonly used anode material through an obvious electron interaction between the Zn atom and the Cu sites linked in the CuZn@MOF chain. By mitigating the zinc dendrite problem, this approach effectively improves the coulombic efficiency, cycle life, and safety of zinc-based flow batteries. The battery incorporating the prepared material demonstrates impressive stability, exceeding 450 cycles without dendrites at a high current density of 320 mA cm−2, paving the way for efficient and reliable energy storage solutions and a sustainable future.