The vertically aligned graphene/graphite/PPy composites electrode and its PPy thickness-dependent electrochemical performance

Exceptional performance which derived from lab-scale electrodes used in electrochemical capacitors often fail to extrapolate to high mass loading conditions considering the trade-off relationship between penetration depth and charge transfer efficiency. A novel graphene/graphite/PPy(polypyrrole) composites fiber is fabricated with vertically aligned channels, offering fast diffusion pathways for the ion. By controlling the time of PPy electrodeposition, the trade-off between the PPy thickness (x) and the width of channels (y) is discussed referring to their electrochemical performance. Understanding the x-y dependent transport kinetics of the three-dimensional microstructural electrode help achieves a higher utilization of active materials. The fabricated all solid-state supercapacitor perform advanced energy density (0.117 mWh/cm2) and power density (26.7 mW/cm2). This study may also provide a guidance for the optimization of pore width and wall thickness of the three-dimensional electrode (or scaffold) design.