An aqueous rechargeable copper ammonium hybrid battery with good cycling performance

Abstract

Hybrid aqueous rechargeable batteries have attracted broad attention due to their cost, safety, and environmental advantages. Nevertheless, a large proportion of the reported long-life and high-power performances are accomplished with a low mass-loading at the cathode (2 mg cm⁻²). To overcome this challenge, we propose an aqueous rechargeable copper ammonium hybrid battery, which includes an NH₄⁺-rich copper hexacyanoferrate (N-CuHCF) cathode, a Cu foil anode and a hybrid aqueous electrolyte (1 M NH₄⁺ + 0.1 M Cu²⁺). Its operation involves a reversible NH₄⁺ insertion/extraction reaction at the cathode and Cu plating/stripping at the anode. The unique working mechanism enables this hybrid-ion battery to show a long-term lifespan (over 10 000 cycles). Moreover, this battery exhibits high specific capacity and a long-life property (1000 cycles) even with a high mass-loading (20 mg cm⁻²) of N-CuHCF at the cathode.