N-Doped Carbon Dots Embedded in Electrospun Cellulose-Derived Nanofibers: A Novel Approach to Pseudosupercapacitors with Enhanced Faradic Activity

The sustainable energy storage landscape is rapidly evolving, with innovations driven by the necessity to meet increasing global energy demands. In this context, pseudosupercapacitors emerge as a new solution, closing the gap between batteries and supercapacitors, by achieving the high energy density of batteries with the rapid charge-discharge cycles of supercapacitors. The key to harnessing the potential of pseudosupercapacitors lies in the development of electrodes that demonstrate superior faradic activities and high-capacity retention.<br/>Our research presents a pioneering effort in this direction, focusing on the synthesis of pseudosupercapacitor electrodes from electrospun cellulose acetate nanofibres embedded with N-doped carbon dots. Electrospinning is a widely used technique known for its adaptability in fabricating carbon fibres. With its intrinsic capability to produce fibres boasting a high surface-to-volume ratio, electrospinning not only permitted the integration of the N-doped carbon dots in the fibres, but also allowed fine control over the fibre diameter and nitrogen concentration. By manipulating electrospinning parameters, we achieved fibres ranging from 220 nm to 850 nm, presenting a trade-off between surface area and mass transport efficiencies. Cellulose acetate was chosen as carbon source and as an alternative to usually employed polyacrylonitrile (PAN), to increase the sustainability of our approach.<br/>The carbon dots, synthesized through a microwave-assisted method using citric acid and urea, showcased a high faradic activity (here include values for faradic capacity and capacity retention after xx cycles) even after the deacetylation and carbonization as they were incorporated into the cellulose acetate matrix. Their N-doped nature contributes to enhanced electronic properties. Pyridinic N and pyrrolic N have been shown to be responsible for active redox sites for faradic activity whereas graphitic N is thought to contribute to the enhancement of conductivity of the resultant electrodes.<br/>In conclusion, we present a multidimensional approach to a novel pseudosupercapacitor electrode fabrication. By integrating microwave-assisted synthesized n-doped carbon dots within electrospun cellulose acetate nanofibres, we not only address the technical challenges of achieving high specific capacitance, but also present an environmentally conscious blueprint. With promising preliminary results in electrochemical and analytical characterization, our research aims to expand the current design of pseudosupercapacitor and their implications for sustainable energy storage.