SiC and N, S-doped carbon nanosheets and lignin-enhanced organohydrogel for low-temperature tolerant solid-state supercapacitors

Abstract

The rational design of porous carbon materials and hydrogel electrolytes with excellent mechanical properties and low-temperature tolerance are significance for the development of flexible solid-state supercapacitors. In this study, we introduce a novel methodology for synthesizing SiC/N, S-doped porous carbon nanosheets from bamboo pulp red liquor (RL). We leverage the SiO2 and the sodium salt in RL as templates and sodium lignosulfonate as sulfur dopants for the pyrolysis process and use NH4Cl as a nitrogen dopant. This innovative approach results in a material with a remarkable specific surface area of 1659.19 m2 g−1, a specific capacitance of 308 F g−1 at a current density of 1 A g−1 and excellent stability. Additionally, we harness alkali lignin extracted from RL to enhance a poly (vinyl alcohol) (PVA) matrix, creating a gel electrolyte with low-temperature tolerance and outstanding mechanical properties. A flexible solid-state supercapacitor, which incorporates our electrodes and gel electrolyte, demonstrates high energy density (5.2 W h kg−1 at 251 W kg−1 power density). Impressively, it maintains 82 % of its capacitance over 10,000 cycles of charge and discharge. This provides a new solution for the development of flexible solid-state supercapacitors.