An Organic Cathode for Potassium Dual-Ion Full Battery

Abstract

Potassium-based dual-ion full batteries (PDIBs) were developed with graphite anode, polytriphenylamine (PTPAn) cathode, and KPF6-based electrolyte. The PDIBs delivered a reversible capacity of 60 mA h g–1 at a median discharge voltage of 3.23 V at 50 mA g–1, with superior rate performance and long-term cycling stability over 500 cycles (capacity retention of 75.5%). Unlike the traditional dual-ion batteries, the operation mechanism of the PDIBs with PTPAn cathode is that the PF6– ions interacted with the nitrogen atom reversibly in the PTPAn cathode and the K+ ions were intercalated/deintercalated into/from the graphite anode during the charge/discharge process.