High-value utilization of corn plants derived biomass carbon materials for potassium ion storage

Biomass derived carbon materials exhibit great potential for K⁺ storage due to their inherent low-cost and hierarchical porous structure that the conventional synthetic chemistry can't be reached. In this study, biomass carbon anodes derived from various parts of corn plants, including stalks, cobs, and leaves, are explored for K+ storage applications. The findings reveal that lignin and ash content play pivotal roles in determining capacity, with KOH activation effectively enhancing lignin content. Moreover, K⁺ storage properties can be further improved by N-doping due to high adsorption and doping content. As a result, the corn cobs derived biomass carbon anode with KOH activation and N-doping delivers a high discharge capacity of 265.3 mAh g⁻¹ at 50 mA g⁻¹, and exhibits a superior capacity retention of 85.3 % over 1000 cycles, which demonstrates the exceptional K⁺ storage performance of biomass carbon materials, and promotes the high-value utilization of biomass wastes.