A facile coating strategy for high stability aqueous zinc ion batteries: Porous rutile nano-TiO2 coating on zinc anode

Rechargeable aqueous zinc ion batteries have attracted significant attention because of their non-toxicity, high theoretical capacity, and low cost. However, many challenges regarding zinc anodes have hindered the development of zinc ion batteries , such as the growth of zinc dendrites, passivation and hydrogen evolution . In this study, a simple strategy based on porous rutile nano-TiO 2 coating was used to guide uniform deposition of zinc ions to inhibit the formation of zinc dendrite. The TiO 2 coated zinc anode shows excellent electrochemical performance . Therefore, for Zn Zn symmetric cell, the zinc anode protected by TiO 2 coating shows reduced voltage hysteresis (50 mV at 0.4 mA cm −2 ). Moreover, for Zn-MnO 2 full cell, the cell with TiO 2 coating also shows excellent cycling performance. The discharge capacity of Zn-MnO 2 full cell is only 27.69 mAh g −1 after 500 cycles, while discharge capacity of Zn@TiO 2 -MnO 2 full cell is up to 89.14 mAh g −1 . This excellent electrochemical performance may be attributed to improved wettability of TiO 2 coated zinc anode, the uniform deposition of Zn 2+ and reduction of Zn dendrites. Overall, this study provides a simple and beneficial strategy for future development of rechargeable aqueous zinc ion batteries .