Facile synthesis of N-doped activated carbon derived from cotton and CuCo_2O_4 nanoneedle arrays electrodes for all-solid-state asymmetric supercapacitor

摘要

Nitrogen-doped activated carbon (NAC) with a high specific surface area was successfully fabricated through graphitization derived from cotton and ammonia doping. The obtained NAC exhibits an enhanced specific capacitance of 156.4Fg(-1) at 0.5Ag(-1) and good cycling stability with capacitance retention of 95% after 5000 cycles. Hydrothermal route was used to synthesize CuCo2O4 nanoneedles with diameter of 20 to 50nm. CuCo2O4 electrode showed good electrochemical performance with specific capacitance of 390Fg(-1) at 0.5Ag(-1) and high stability. Based on the two electrodes, an all-solid-state asymmetric supercapacitor (ASC) was assembled, which can achieve specific capacitance of 26.2Fg(-1) at 1Ag(-1), energy density of 8.2Whkg(-1) at a power density of 750Wkg(-1) and still retains 5.6Whkg(-1) at power density of 7500Wkg(-1). Two ASCs in series successfully illuminated 52 LEDs connected in parallel, indicating the practical application of the device.