High Conductive Architecture: Bimetal Oxide with Metallic Properties @ Bimetal Hydroxide for High-performance Pseudocapacitor

•The Ni and Co-based composite is applied for pseudocapacitor electrode.•The metallic NiCo2O4 improves the conductivity of the composite.•The composite has 4.625 F cm−2 areal capacitance and 94.66% capacity retention.

Poor electronic and ionic conductivities of electrode limit the development of pseudocapacitor. In this study, the NiCo2O4 nanowires array @ NiCo(OH)2 nanosheets growth on Ni foam as a binary composite electrode is synthesized by hydrothermal and electrodeposition methods to improve the electrochemical performance of pseudocapacitor. In the composite electrode, the NiCo2O4 exhibits metallic properties, which is verified by the first principles calculation, and is responsible for the high conductivity of the composite electrode. Electrochemical measurements demonstrate the NiCo2O4 @ NiCo(OH)2 electrode exhibits a high areal capacitance of 4.625 F cm−2 at 1 mA cm−2 (2890.6 F g−1 at 0.625 A g−1) and an excellent cycling stability (maintaining 94.66% capacity after 5000 cycles at 10 mA cm−2). Therefore, this work further extends the research on high conductive architecture electrode and shed some light on the design of applied materials for the future practical energy storage devices.

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