The Polymer Society of Korea

Abstract

Potassium-ion batteries are emerging as promising alternatives to lithium-ion batteries due to the natural abundance and low cost of potassium. However, the large ionic radius of K⁺ severely limits diffusion kinetics and structural stability in conventional graphite anodes. In this presentation, we report a template-free, self-assembly strategy to fabricate nitrogen and phosphorus co-doped three-dimensional porous carbon with tunable morphology and hierarchical pore architecture. By controlling the melamine-to-phytic acid ratio, the resulting carbon framework exhibits expanded interlayer spacing, high surface area, and abundant defect sites, all of which are favorable for potassium-ion storage. Among the synthesized materials, the optimized N3P1 electrode delivers a high reversible capacity of 258 mAh g⁻¹ at 0.1 A g⁻¹ and maintains 96.1% capacity retention over 800 cycles at 0.5 A g⁻¹. Kinetic analysis reveals that potassium storage is dominated by surface-controlled capacitive behavior, enabled by the synergistic effects of N,P co-doping and the well-developed 3D porous structure. Ex-situ TEM analysis further confirms the reversible interlayer expansion and structural stability during repeated K⁺ insertion and extraction. This work demonstrates that simultaneous morphological control and heteroatom co-doping, achieved through a simple self-assembly process, is an effective design strategy for high-performance potassium-ion battery anodes and can be extended to other advanced carbon-based energy storage systems.