Ball-milling fabrication of PPy/Ni2P/GO composites for high-performance supercapacitor electrodes

Polypyrrole (PPy) is a promising candidate for supercapacitor electrode materials owing to its high electric conductivity and large specific capacitance. However, the poor cycling performance and the mechanical deformation of PPy remain to be challenges. Here, PPy/Ni2Ploaded graphene oxide (PPy/Ni2P/GO) is fabricated via a simple ball-milling process. The as-prepared PPy/Ni2P/GO composites exhibit a high specific capacitance of 741.5 F g-1 at 1 A g-1, good rate capability (81.4% of capacitance at 10 A g-1), and long-term cycling stability (89.76% retention after 5000 cycles at 1 A g-1).When used in the asymmetric supercapacitor, the PPy/Ni2P/GO//AC (active carbon) device exhibits the energy density of 61 Wh kg-1 at the power density of 849.8 W kg-1 and excellent cycling performance (89.4% capacitance retention after 3000 cycles at 10 A g-1). The excellent electrochemical performance is owed to the high surface area and high hydrophilicity of the PPy/Ni2P/GO composites, coupled with good electron conductivity of the graphene oxide, which lead to reduced ion diffusion lengths and low charge transfer resistance. These results demonstrate that PPy/Ni2P/GO composites are promising as electrodes for supercapacitors.