Poly(anthraquinonyl sulfide) cathode for potassium-ion batteries

•We, for the first time, introduce PAQS as a cathode for potassium ion batteries•PAQS delivers, to date, the highest capacity of 200 mAh/g as a cathode•PAQS shows good cycling performance in the electrolyte of KTFSI/DOL + DME

Potassium-ion batteries (KIBs) are a promising sustainable energy storage technology due to the high abundance and low cost of potassium. Carbon anode materials for KIBs have seen great successes, but the development of cathode materials is yet to catch up. In this study, poly(anthraquinonyl sulfide) (PAQS) is evaluated as a cathode material for KIBs. It exhibits a high reversible capacity of 200 mAh/g, which is the highest value for a potassium storage cathode material. The cell shows two slopes averaged at 2.1 and 1.6 V vs. K+/K. It shows a good cycling performance with the capacity retention of 75% after 50 cycles at a rate of C/10. These preliminary results indicate that PAQS is a promising cathode material for KIBs.

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