One-Step Wet-Spinning of High-Energy Density Coaxial Fibrous Supercapacitors Based on In Situ Carbon-Modified Nitrogen-Doped MXene Nanosheets

Fibrous supercapacitors (SCs) are emerging promising power sources for flexible/wearable electronics and have attracted an extensive amount of attention from researchers. However, the low energy density has always hindered their further development. Here, a coaxial fibrous SC (CFSC) was fabricated by one-step wet-spinning combined with an electrodeposition strategy. Benefiting from the large surface area and abundant pore structure of carbon-modified nitrogen-doped MXene nanosheets (NS), as well as the high conductivity of silver (Ag) NS, the electrolyte ion/electron transport paths are significantly improved. Furthermore, the distributed GO in the P(VDF-HFP) separator could form a high-speed continuous ion transport channel, thus enhancing the ionic conductivity. At a power density of 40–200 μW cm –2, the CFSC shows a high energy density of 0.7–3.39 μWh cm –2 . The as-prepared CFSC also maintains an excellent capacitance retention rate of 90.3% even after 15 000 charge–discharge cycles. This work provides a general strategy for manufacturing high-performance, flexible, and wearable SCs.