Nitrogen-doped Carbon Microfiber with Wrinkled Surface for High Performance Supercapacitors

In this work, nitrogen-doped carbon microfiber (NCMF) is fabricated via a facile co-assembly of natural silk and graphene oxide (GO) and the following thermal treatment. The amphiphilic nature of GO endows NCMF a crumpled surface with a high surface area of 115 m(2) g(−1). As the binder-free electrode in electrical double-layer capacitors, NCMF shows an excellent capacitance of 196 F g(−1) at scan rate of 5 mV s(−1), which is almost four times higher than that of the pristine CMF from silk (55 F g(−1)). Additionally, the capacitance of NCMF can be kept around 92 F g(−1) at a high scan rate of 300 mV s(−1) even after 10000 cycles. More importantly, a high energy density (≈22.7 μW h cm(−2)) and power density (≈10.26 mW cm(−2)) are achieved by the all-solid-state supercapacitor based on NCMF.