Nanocellulose-derived carbon nanosphere fibers-based nanohybrid aerogel for high-performance all-solid-state flexible supercapacitors

In order to meet the urgent needs of portable and flexible devices in today’s society, it is strongly demanded to develop a next-generation, low-cost, flexible, lightweight, and sustainable supercapacitor system with high electrochemical performance and good operational safety. Here, a new type of highly flexible and lightweight all-solid-state supercapacitor is developed by using the freestanding and highly porous nanohybrid aerogel films consisting of carbon nanosphere fibers (CNPFs)/molybdenum disulfide (MoS ₂ )/reduced graphene oxide (RGO) as electrodes and using H ₂ SO ₄ /polyvinyl alcohol (PVA) gel as electrolyte. The CNPFs/MoS ₂ /RGO nanohybrid aerogels are prepared by one-step pyrolysis of the nanocellulose fibers (NCFs)/MoS ₂ /graphene oxide (GO) aerogels obtained via freeze-drying process. During the pyrolysis process, the NCFs is carbonized to CNPFs and the GO is thermally reduced to RGO. The as-prepared all-solid-state flexible supercapacitors exhibit high specific capacitance of 1144.3 F g ⁻¹ at 2 mV s ⁻¹ with good cycling stability of more than 98% of the capacitance is retained after 10,000 charge–discharge cycles at a current density of 5 mA cm ⁻² . Moreover, they can deliver high energy density and power density which are up to 57.5 µW h cm ⁻² (28.8 W h kg ⁻¹ ) and 29.1 mW cm ⁻² (14.5 kW kg ⁻¹ ), respectively. Therefore, we provide the highly porous CNPFs/MoS ₂ /RGO nanohybrid aerogels with characteristics of superior electrochemical performance, remarkable bending stability, environmental friendliness and low cost will be a potential promising electrode material for highly flexible all-solid-state supercapacitors.