Boosting the potassium-ion storage performance of a carbon anode by chemically regulating oxygen-containing species.

The oxygen-containing species in melamine foam carbons are chemically regulated by oxidizing-acid treatment. The optimized carbon anode shows an enhanced potassium-storage performance in terms of reversible capacity, rate performance, and long-term cycling stability. Both structural analysis and theoretical calculations highlight the roles of quinone- and ether-type oxygen species in boosting the potassium-ion storage performance.