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. • Rutile nano-TiO 2 coating with uniform porous structure is used as protection layer for zinc anode. • Rutile nano-TiO 2 layer is coated on zinc anode via a facile strategy. • Coated zinc anode exhibits good hydrophilicity. • Coated zinc anode greatly improves cycle performance of aqueous zinc ion battery.