Hierarchical nano-architectonics of porous carbon from an interpenetrating Gel-CNTs network via salt-templated strategy for high-performance supercapacitors.

Abstract

Biomass-derived carbon materials offer considerable potential for sustainable supercapacitors (SCs) electrodes, yet the practical application is often limited by their unstable structure, insufficient continuous conductive networks and inevitable corrosive activation processes. Herein, hierarchical porous carbon materials were fabricated through a nano-architectonic strategy that combines salt-templated activation with the construction of conductive network. Specifically, NaNO₃ serves simultaneously as a sacrificial template and a mild activator to generate interconnected hierarchical frameworks, while the interpenetrating gelatin/carbon nanotubes (CNTs) network establishes continuous 3D conductive pathways that support efficient electron transport and preserve structure integrity. The resulting carbon exhibits a high specific surface area (2204.2 m²/g), hierarchical porosity, and enhanced electrical conductivity, which endow the material with high capacitance performance and reliable electrochemical stability. In a three-electrode system, the CNGC-derived electrode delivers a specific capacitance of 351.7F/ g at 1 A/g, retaining 70.1 % at 50 A/g. The symmetric supercapacitor assembled with Na₂SO₄ electrolyte achieves an energy density of 40.84 Wh/kg at 1000 W/kg and maintains 98.3 % capacitance retention over 10,000 cycles. The rational combination of biomass-derived molecular networks, nanoscale conductive fillers, and salt-templated pore architecture provides a promising pathway toward structurally coherent and functionally integrated carbon materials for electrochemical energy storage.