Preparation and Electrochemical Performance of Leaf-Derived N/O-Rich Doped Porous Carbons

Abstract

This research focuses on the field of supercapacitor electrode materials. Using Rhus typhina leaves as the starting material, it innovatively applies a mixed activator composed of K₂CO₃ and ZnCl₂ and successfully prepares O/N self-doped leaf-derived porous carbon electrode materials (TLMPC-x) through a precisely controlled two-step carbonization-activation method. The aim is to develop a new type of electrode material that combines excellent performance, environmental friendliness, and the advantage of low cost, and to deeply explore the mechanism of the effect of the activator ratio on the specific surface area and electrochemical performance of the materials. Among them, TLMPC-1.0 remarkably exhibits a specific surface area as high as 2827.9 m² g⁻¹. Its abundant and multi-level pore structure complements well with the diverse heteroatom doping. During the electrochemical performance test in the KOH electrolyte system, the specific capacitance of this material excellently reaches 335.3 F g⁻¹, and the capacitance retention rate is stably maintained at 69%. When the power density is 250 W kg⁻¹, an energy density of 9.45 Wh kg⁻¹ can be achieved. Moreover, after 20 000 charge–discharge cycles, its capacitance retention rate is still as high as 96.4%, demonstrating extremely excellent electrochemical performance and ultra-stable cycle stability.