Carbon dots modified Ti3C2Tx-based fibrous supercapacitor with photo-enhanced capacitance

The energy crisis has always been a widely concerned problem. It is an urgent need for green and renewable energy technologies to achieve sustainable development, and the photo-assisted charging energy storage devices provide a new way to realize the sustainable utilization of solar energy. Here, we fabricated a photo-assisted charging fibrous supercapacitor (NM2P1) with Ti3C2Tx-based hybrid fibre modified by nitrogen-doped carbon dots (NCDs). The NM2P1 fibre provides a volumetric capacitance of 1,445 F·cm−3 (630 F·g−1) at 10 A·cm−3 under photo-assisted charging, which increases by 35.9% than that of dark condition (1,063 F·cm−3/464 F·g−1). Furthermore, the NM2P1 fibrous supercapacitor device shows that the maximum volumetric energy density and volumetric power density are 18.75 mWh·cm−3 and 8,382 mW·cm−3. Notably, the transient photovoltage (TPV) test was used to further confirm that NCDs as a photosensitizer enhance the light absorption capacity and faster charge transfer kinetics of NM2P1 fibre. This work directly exploits solar energy to improve the overall performance of supercapacitor, which opens up opportunities for the utilization of renewable energy and the development of photosensitive energy equipment.