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

摘要

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 Kion 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 KNO3 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.