Abstract
Aqueous zinc batteries are among the most promising large-scale energy storage technologies but their practical application is hindered by the low redox reversibility of Zn anode in aqueous electrolytes. In this work, an indium-coated carbon-zinc composite (ICZ) anode is demonstrated with outstanding cyclic stability in classic aqueous zinc sulfate electrolytes. Compared with Zn and the carbon-zinc composite (CZ) anodes, the ICZ anode reduces the high overpotential required for Zn nucleation, and prevents high-rate HER and its related parasitic reactions, endowing high redox reversibility of the ICZ anode. Consequently, the ICZ anode enhances the cyclic stability of zinc ion batteries and zinc ion capacitors. The practical potential of the ICZ anode is demonstrated by an ICZ//porous carbon pouch cell delivering a high areal capacity of 4.7 mAh cm−2 at 6 mA cm−2. Our work provides an effective redox-kinetics regulation strategy for Zn anodes in aqueous zinc batteries.
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•An indium-carbon composite coating layer is utilized to boost the reversibility of Zn anode.•Poor cycling stability of Zn foil is elucidated by the GCD curves and microscopy images.•High energy barrier for Zn nucleation triggers high-rate parasitic reactions.•The ICZ anode shows superior effects in suppressing parasitic reactions.•The ICZ pouch cell achieves a high areal capacity of 4.7 mAh cm−2 at 6 mA cm−2.