N-, P-, and Ni-Co-doped Porous Carbon from Poplar Powder and Graphene Oxide Composites as Electrode Materials for Supercapacitors
Zhe Yuan, Yunhan Ma, Pengxue Zhang, Minghao Zhai, Chuanli Qin, Xiankai Jiang
Abstract
Poplar powder was used as a raw material to prepare an electrode material in supercapacitors by doping modification, carbonization, and activation. The lignin-removed poplar powder was mixed with graphene oxide, melamine, and diammonium hydrogen phosphate and then compounded with nickel sulfate. Upon carbonization and activation with KOH, the composite becomes a hierarchical porous carbon material with a pore volume of 0.93 cm 3 g –1 and a surface area of 1214.1 m 2 g –1 . At 0.5 A g –1 current per square meter, the specific capacitance was 407.5 F g –1 . In addition, 92.6% of the capacitance remained even after 3000 charging and discharging cycles. There was an outstanding power and energy density of 12.32 W h kg –1 at 499.99 W kg –1 for a symmetric supercapacitor in 6 M KOH. Co-doped porous carbon with nitrogen, phosphorous, and nickel could be a good electrode material for energy storage devices.