Preparation of carbon-based monolith with macroporous-mesoporous structure derived from PVDF hollow fiber membranes for supercapacitors

In this work, a carbon-based monolith with macroporous-mesoporous structure derived from polyvinylidene fluoride (PVDF) hollow fiber membranes is reported. The Co2+ soaked PVDF hollow fiber membranes are treated with vinyltrimethoxysilane (VTMS) and calcined at relatively low temperatures (600 °C) to obtain a carbon-based material with a distinctive honeycomb porous structure. The VTMS treatment is the committed step, which provides a hard SiO2 protective layer for the PVDF hollow fiber membrane during the calcination process to support the skeleton structure and prevent the macrostructure collapse and also plays a role in expanding mesopores. The obtained hierarchically porous structure can improve the electrochemical activity of the carbon-based material. In a three-electrode system, the specific capacitance of 701.0 F g−1 can be achieved at a current density of 1 A g−1, and the retention rate is 112.1 % after 10,000 cycles at 10 A g−1. The assembled quasi-solid-state symmetric supercapacitor can be operated in a 0–1.4 V voltage window, and it demonstrates an energy density of 26.3 Wh kg−1 at the power density of 349.9 W kg−1.