Developing a high-performance aqueous zinc battery with Zn2+ pre-intercalated V3O7·H2O cathode coupled with surface engineered metallic zinc anode

Abstract

• Zn 2+ intercalation capacity in V 3 O 7 ,nH 2 O 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 Zn 2+ plating/stripping overpotential and regulates dendrite less Zn 2+ plating. • C@Zn//Zn-V 3 O 7 ·H 2 O full cell showed improved cycling performance over Zn//Zn-V 3 O 7 ,nH 2 O. Herein we demonstrate a high-performance full cell aqueous zinc ion battery with structurally engineered V 3 O 7 ·H 2 O cathode and surface modified metallic zinc anode. We demonstrate that the capacity, rate performance and stability of V 3 O 7 ·H 2 O cathode can be significantly improved via Zn 2+ pre-intercalation, which acts as a pillaring agent to stabilize the cathode against structural degradation. The pre-intercalated V 3 O 7 ·H 2 O 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 V 3 O 7 ·H 2 O, 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 Zn 2+ 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-V 3 O 7 ·H 2 O and V 3 O 7 ·H 2 O cathode, which showed much improved cycling stability compared to that of unprotected metallic zinc.