Soft-hard carbon composites for high-mass-loading aqueous supercapacitors with enhanced performance

Abstract

With growing global concern for energy and environmental challenges, high-value utilization of organic solid wastes such as plastics and biomass has become crucial. The material CP-HPC was fabricated as a 2D porous heterostructure through the composite of soft (PET-derived) and hard (chitosan-derived) carbon components. The optimized CP-HPC-4 possesses a substantial specific surface area of 2710 m 2 g −1 and a hierarchical pore network that ensures efficient ion transport, alongside a favorable electrical resistivity of 0.25 Ω cm. This unique soft-hard carbon integration endows the supercapacitor with high capacitance and excellent rate performance even at high mass-loadings. The high mass loading supercapacitor assembled by CP-HPC-4 shows outstanding capacitance of 329.57 F g −1 at 0.1 A g −1 , low open-circuit voltage attenuation rate (21.85 mV h −1 ), high voltage retention rate (78.29%), and remarkable cycling stability (94.14% retention after 10,000 cycles). The superior charge storage is attributed to the enhanced K + adsorption affinity and facilitated diffusion kinetics of the heterostructure, confirmed by density functional theory (DFT) and molecular dynamics (MD) simulations. The soft-hard carbon composites effectively mitigate the electrochemical inadequacies inherent to each material alone, thereby offering a novel pathway to reconcile the dual imperatives of environmental protection and efficient energy storage.