Abstract
•Zn2+ intercalation capacity in V3O7,nH2O could be significantly increased with Zn(II) chemical preinsertion.•Nanocarbon derived from candle shoot has been employed as artificial SEI to protect metallic Zn anode.•Nano carbon as SEI reduce the Zn2+ plating/stripping overpotential and regulates dendrite less Zn2+ plating.•C@Zn//Zn-V3O7·H2O full cell showed improved cycling performance over Zn//Zn-V3O7,nH2O.
Herein we demonstrate a high-performance full cell aqueous zinc ion battery with structurally engineered V3O7·H2O cathode and surface modified metallic zinc anode. We demonstrate that the capacity, rate performance and stability of V3O7·H2O cathode can be significantly improved via Zn2+ pre-intercalation, which acts as a pillaring agent to stabilize the cathode against structural degradation. The pre-intercalated V3O7·H2O cathode showed an improved specific capacity (404 mAh/g at 0.1 A/g) and rate capability (235 mAh/g at 2 A/g), which was much higher than the pristine V3O7·H2O, which showed specific capacity of 316 mAh/g and 141 mAh/g at 0.1 A/g and 2 A/g, respectively. Further we demonstrate that the Zn2+ plating stripping overpotential and the uncontrollable dendrite growth at the metallic zinc anode can be significantly reduced with surface engineering of metallic zinc with a thin layer of carbon coating. We followed a simple and economical approach to obtain the nanocarbon from candle shoot, which could be coated uniformly onto the metallic zinc with controllable thickness. We demonstrate the efficacy of the C@Zn as anode by coupling it with both Zn-V3O7·H2O and V3O7·H2O cathode, which showed much improved cycling stability compared to that of unprotected metallic zinc.