11,11,12,12-tetracyano-9,10-anthraquinonedimethane as a high potential and sustainable cathode for organic potassium-ion batteries.

We fabricated a potassium-ion battery by using 11,11,12,12-tetracyano-9,10-anthraquinonedimethane (TCAQ) as the cathode for the first time. Owing to the unique molecular structure and configuration of ionic liquid electrolytes, TCAQ shows a high redox potential of 2.6 V vs. K+/K while delivering a capacity of 88 mAh g-1 at a current density of 17 mA g-1 and a capacity retention of 61% after 50 cycles. The mechanism of the reaction of TCAQ with K was investigated. The results prove that TCAQ holds great promise for broad applications in potassium-ion batteries while revealing new scientific insights into K+-organic cathode batteries.