Tracing Structural Evolution of Maillard-Derived Carbon Skeletons for Advanced Zinc-Ion Hybrid Supercapacitors

Abstract

Biomass-derived carbon materials are promising for energy storage due to their sustainability and low cost, but often suffer from limited surface area, poor porosity, and insufficient active sites. To address these issues, nitrogen-doped carbon (BC-GA) with a groove-nested porous structure was synthesized via Maillard reaction between glucose and glycine at 550 °C, followed by KOH etching and calcination. This process enabled uniform nitrogen doping and surface modification, while creating a hierarchical pore structure tailored to match the size of solvated Zn²⁺ ions (0.86 nm). When applied in symmetric supercapacitors (BC-GA//BC-GA), the material exhibited a synergistic dual–mechanism storage behavior, delivering a specific capacitance of 103.1F g⁻¹ at 2 A g⁻¹ and retaining 65% at 16 A g⁻¹. In zinc-ion hybrid supercapacitors (BC-GA//ZnSO₄(aq)//Zn), it achieved a high energy density of 165 Wh kg⁻¹ and a power density of 400  W kg⁻¹, simultaneously demonstrating practical ability to power an electronic watch. This work offers a new strategy for enhancing biomass carbon through reaction and etching control.