Fabrication of Co3O4@Co–Ni sulfides core/shell nanowire arrays as binder-free electrode for electrochemical energy storage

•Co3O4@Co–Ni-sulfides has been prepared without the common anion exchange process.•The binder-free electrode shows enhanced pseudocapacitive performance.•An asymmetric supercapacitor based on this hybrid electrode has been assembled.

The rational design and construction of efficient electrodes for applications in energy storage have been widely conducted. In this work, we have demonstrated a binder-free electrode composed of Co3O4@Co–Ni-sulfides core/shell nanowire arrays with tunable Ni/Co ratio for the high-performance pseudo-capacitors. This as-fabricated electrode can offer the desired structural features for the efficient usage of active materials. With the advantages of the well-ordered architecture, this hierarchical electrode shows a high specific capacitance of 1844 F g−1 (7.38 F cm−2) at a current density of 5 mA cm−2. Besides, an asymmetric supercapacitor based on this synthesized electrode can deliver a maximum energy density of 44.8 Wh kg−1 and a good cycling stability of 91% retention after 4000 cycles. Our results presented here demonstrate that this hierarchical electrode has potential usage in electrochemical energy storage.

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