A general in-situ etching and synchronous heteroatom doping strategy to boost the capacitive performance of commercial carbon fiber cloth

The flexible solid-state supercapacitor (FSSC) has attracted many attentions due to its feature of high power density with stable cycling performance, as well as lightweight and flexible features and is expected as an ideal candidate power supply for portable and wearable electronics devices. In general, the electrode plays an important role in determining the overall performance of the FSSC. Therefore, to meet the requirement of practical applications, a simple, facile and environment friendly strategy to prepare deformable/flexible electrodes with high energy density is the target issue to be considered. Herein, we report a generalized “soaking-recrystallization-calcination” method to enhance the capacitance performance of commercialized carbon fiber cloth. Thanks to the in-situ etching process to increase the surface area and the synchronous heteroatom doping to induce pseudocapacitive behavior, the resultant activated carbon fiber cloth sample exhibits an ultra-high areal capacitance up to 362 mF cm−2, is about 1448 fold enhancement than that of fresh carbon fiber cloth calcined at 750 °C. Meanwhile, the assembled FSSC based on the activated carbon fiber cloth exhibits a maximum volumetric energy density of 0.35 mWh cm−3and gravimetric energy density of 0.84 Wh kg−1. Such results represent a novel and promising direction to prepare high performance flexible electrode for FSSC application.