Dendrite-free Zn anodes enabled by a hierarchical zincophilic TiO2 layer for rechargeable aqueous zinc-ion batteries

Aqueous zinc ion batteries (ZIBs) have received significant attention owing to their low cost, high energy density, good safety, and environmental friendliness. However, the unavoidable growth of dendrites during uneven stripping/plating of Zn and extreme polarization hinders the practical application of zinc ion batteries. Herein, we report a dendrite-free ZIB anode via mesoporous zincophilic TiO2 nanoparticle to construct a hierarchical nanostructured layer and to chemically accommodate the formation of Zn dendrite. This hierarchical zincophilic TiO2 layer on the Zn surface (hmTO-Zn) plays a crucial role in contributing to reduce dendrite growth and significantly improves the electrochemical performance of ZIBs. Ultralong cycle life and high rate performance are demonstrated in hmTO-Zn|Zn(CF3SO3)2|V2O5 rechargeable aqueous ZIBs. A battery with an hmTO-Zn electrode delivers excellent capacity (102 mAh/g) at a high current density (5000 mA g−1) after ultralong life (5000 cycles) with almost 100 % coulombic efficiency compared to a battery with a bare zinc anode (44 mAh/g after 5000 cycles). These results give a novel approach necessary to improve ZIBs further to make it a worthy and safe energy device in field of large scale energy storage solutions.