Construction of flexible cellulose nanofiber fiber@graphene quantum dots hybrid film applied in supercapacitor and sensor

Cellulose nanofiber (CNF) materials have attracted increasing attention in the field of energy storage and sensing due to their flexibility, environmental protection and sustainability. However, CNF materials have poor conductivity and low utilization effciency, which limits their applications. Improving the conductivity and utilization efficiency of CNFs while retaining their advantages is of great significance for developing wide applications of biomass resources. In this work, noncarbonized CNF@graphene quantum dot (GQD) film with good flexibility was fabricated through a combination of electrolysis and liquid dispersion. The as-obtained hybrid film shows excellent electrochemical storage performance, mechanical properties and sensing characteristics. Specifically, the film presents a specific capacitance of 118 mF cm(- 2) even at a ultrahigh scan rate of 1000 mV s(- 1), and a high capacitance retention higher than 93% at different current densities after 5000 cycles. Additionally, the assembled supercapacitor based on the hybrid film possesses high power and energy density at the same time (782 mW cm(- 2) and 596 mu Wh cm(- 2)). These results demonstrate that the hybrid film possesses excellent rate performance and cycle stability. In addition, the film is sensitive to movement of the human body.