Bacterial cellulose derived carbon nanofiber aerogel assembled with redox active hydrogel and alpha-MoO3 nanoplate for high-performance supercapacitors

Abstract

Dual-asymmetric supercapacitors (DASCs) with high capacitive performance were developed in this work through carefully design and configuration of all the capacitor components. Free-standing carbon aerogel was directly utilized as the positive electrode, which was fabricated by pyrolyzing bacterial cellulose (BC) aerogel. Its porous structure afforded it excellent interface with the redox active electrolyte. Redox active hydrogel electrolyte based on mixed-valence iron ions (PVA/H2SO4/Fe3+/2+) was prepared with a freezing-thawing method and combined with the carbon aerogel to form the positive compartment of the capacitors. Meanwhile, α-MoO3 nanoplates were fabricated by hydrothermal method and used for the fabrication of negative electrodes, which were assembled with conventional PVA/H2SO4 hydrogel electrolyte to form the negative compartment. The as-assembled DASCs showed a specific capacitance of 560.8 F g−1 at 1 A g−1 and energy density of 131.6 Wh kg−1, indicating its remarkable capacitive performance. Moreover, the optimized DASC displayed a remarkable long-term cycling stability. This work on the design and assembly of the battery-like supercapacitor with carbon aerogel electrodes combined with their corresponding hydrogel electrolytes afforded a new configuration to fabricate the devices with high performance.