Free-standing carbon electrode materials with three-dimensional hierarchically porous structure derived from waste dyed silk fabrics

Abstract An easy one-step pyrolysis method without any activation was employed to convert a waste dyed silk fabric into an interconnected hierarchically porous free-standing carbon fabric. As a result, nitrogen and oxygen co-doped carbonized dyed silk fabric with blue dye (CSF-B) exhibits a high specific capacitance of 305.02 F g−1 at a scan rate of 2 mV s−1 using 1 M Na2SO4 electrolyte and a good cycling life stability with only 10% capacitance loss after 5000 cycles. Moreover,supercapacitor assembled by two CSF-B electrodes shows an energy density of 10.73 Wh kg−1 at a power density of 160.71 W kg−1. This exciting results display a green and low-cost design of self-supporting carbon electrode materials for supercapacitors with high performance. Interestingly, this concept can be readily extended to other waste fabrics such as cotton, wool and synthetic fiber dyed fabrics, which is beneficial to effectively utilize waste textile to create high value-added products.