A novel aqueous zinc-ion battery capable of self-charging at low temperature

Abstract

Lately, there has been growing enthusiasm in self-charging power systems that integrate energy harvesting and storage technologies. Nonetheless, conventional integrated systems are heavily reliant on specific energy sources and often have complex configurations. In contrast, a chemically self-charging zinc-ion battery (ZIB) offers a simplified design and enhanced adaptability. The battery can operate without the need for external power generation equipment, reducing dependence on specific energy sources and providing greater versatility under different environmental conditions. In this study, we develop a chemically self-charging aqueous zinc-ion battery (ZIB) incorporating an FeVO₄·H₂O cathode and Zn anode coupled with an aqueous electrolyte containing 1 m Zn(CF₃SO₃)₂ and 5.16 m LiTFSI. This battery exhibits good self-charging capabilities and electrochemical performances at both 25 °C and 0 °C. This work is the first effort to realize a chemically self-charging zinc-ion battery that demonstrates self-charging capability at low temperature. Different self-charging durations are investigated to attain the optimum open circuit voltage (OCV) and discharge capacity. Following 12 hours of oxidation in air, the ZIB achieves a capacity of 284.33 mA h g⁻¹ at 0.2 A g⁻¹ at 25 °C and 117.686 mA h g⁻¹ at 0.2 A g⁻¹ at 0 °C, indicating commendable self-recharge capability. The OCV after 12 hours is measured to be 0.996 V at 25 °C and 0.859 V at 0 °C. The as-prepared self-charging battery capable of operating at 0 °C is crucial to practical applications in cold climates, such as automotive, outdoor devices, and renewable energy systems.