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/cm(2)) and power density (26.7 mW/cm(2)). This study may also provide a guidance for the optimization of pore width and wall thickness of the three-dimensional electrode (or scaffold) design. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

A novel graphene/graphite/PPy composite fiber with vertically aligned channels was fabricated, providing fast diffusion pathways for ions and improving electrochemical performance for higher utilization of active materials. By controlling the deposition time of PPy, the trade-off relationship between PPy thickness and channel width was discussed to enhance energy and power density of the supercapacitor. This study may guide the optimization of pore width and wall thickness in three-dimensional electrode design.