A cellulose-based hybrid 2D material aerogel for a flexible all-solid-state supercapacitor with high specific capacitance

As one of the energy storage devices, all-solid-state flexible supercapacitors have attracted significant attention because of their high power density, low cost, high safety, low environmental impact, and long cycle life. In this study, a new type of all-solid-state flexible supercapacitor that uses cellulose nanofibers (CNFs)/molybdenum disulfide (MoS₂)/reduced graphene oxide (RGO) hybrid aerogel film as an electrode material and charge collector and H₂SO₄/polyvinyl alcohol (PVA) gel as an electrolyte and separator has been demonstrated. These aerogels are prepared by supercritical CO₂ drying, which use CNFs as an effective, environmentally friendly, and steady dispersant of MoS₂ and RGO. Owing to the porous structure of the electrodes and the remarkable electrolyte absorption properties, the supercapacitors exhibit excellent electrochemical properties. The specific capacitance calculated from the cyclic voltammogram curves at a scan rate of 2 mV s^-1 is about 916.42 F g^-1. The capacity retention is more than 98% after 5000 charge-discharge cycles at a current density of 0.5 mA cm^-2. Additionally, the areal capacitance, areal power density, and energy density of the supercapacitors are about 458.2 mF cm^-2, 8.56 mW cm^-2 (4.3 kW kg^-1), and 45.7 μW h cm^-2 (22.8 W h kg^-1), respectively. Owing to its low cost and environmental friendliness, CNFs/MoS₂/RGO nanohybrid aerogel has great application potential as an electrode material of all-solid-state flexible supercapacitors.