Aqueous K-ion battery incorporating environment-friendly organic compound and Berlin green

Abstract

Aqueous rechargeable metal-ion batteries (ARMBs) hold intrinsic advantages of high safety, low cost and environmental benignity for large scale energy storage technologies. However, the research on aqueous K-ion batteries (AKIBs) was hindered by limited materials. Herein, a novel AKIB was reported by employing environment-friendly 1,4,5,8-naphthalenetetracarboxylic dianhydride-derived polyimide (PNTCDA) as anode and Berlin green (FeHCF) as cathode. Both electrodes have high rate performance and excellent capacity retention during cycling. Kinetics researches verify the superior electrochemical property of PNTCDA in saturated KNO 3 solution. In-situ XRD of FeHCF demonstrates the unique shift of peak position and negligible distortion of lattice during the insertion/extraction of K + . The AKIB exhibits an attractive energy density of 46.9 Wh/kg and a high capacity retention of 74% in 300 cycles. More importantly, the battery can reach a super-high power of 2079.1 W/kg with an energy density of 24.2 Wh/kg, ranking relatively high among the ARIMs. This system extends the use of polyimide and points a way of AKIBs for grid-scale energy storage. The environment-friendly polyimide and Berlin green are optimized to assemble an aqueous K-ion battery, which possesses high power density, decent cycling stability and attractivity for large-scale stationary energy storage.