Construction of 3D polypyrrole/CoS/graphene composite electrode with enhanced pseudocapacitive performance

Herein, 3D graphene/nickel foam (GE/NF) composite matrix was successfully fabricated by using NF as template through a self-catalytic thermal chemical vapor deposition process. By using the prepared GE/NF as substrate, CoS nanosheets were deposited via a facial one-step electrochemical deposition method. Owing to the advantage of GE in boosting the electrical contact between the electroactive host material and current collector, the as-prepared 3D CoS/GE/NF electrode demonstrated a superior capacitance value of 2308 F g(-1) at 1 A g(-1) and a high rate capability of 70.49% at 20 A g(-1). After depositing the polypyrrole (PPY) film on 3D CoS/GE/NF electrode, the electrochemical performance of CoS was further greatly improved and delivered an extremely high capacitance value of 3450 F g(-1) at 1 A g(-1), with good rate capability (62.61% at 20 A g(-1)) and improved cycling stability. The enhanced electrochemical performance of PPY/CoS/GE/NF electrode is closely related to the advantage of PPY film in increasing the electrical conductivity and reinforcing the integrity of electrode.