Microwave-assisted anchoring of flowerlike Co(OH)2 nanosheets on activated carbon to prepare hybrid electrodes for high-rate electrochemical capacitors

•Microwave-assisted method anchored the flowerlike Co(OH)2 on active carbon.•Carbon supports facilitates the dispersion of Co(OH)2 nanosheets.•Co(OH)2 hybrid nanostructures provides appropriate pathways for charges.•Optimized Co(OH)2/BAC structures were realized for excellent capacitive performance.

Flower-like α-Co(OH)2 nanosheets are in-situ grown on the surface of activated carbon supports for supercapacitors via a facile and cost-effective microwave-assisted method. The existence of carbon supports facilitates the dispersion of pseudocapacitive Co(OH)2 nanosheets and also provides appropriate pathways for charges while charging and discharging. The obtained hybrid architectures can provide a high specific capacitance up to 345 F g−1 at 0.1 A g−1, and still retain 284 F g−1 at a current density as high as 5 A g−1. In addition, benefited from the stable hybrid nanostructures, an excellent electrochemical stability is achieved with an only 16% capacitance degradation after 15,000 charge-discharge cycles at a high current density of 5 A g−1. The impressive electrochemical performance is ascribed to the synergistic effect of porous carbon substrates and pseudocapacitive Co(OH)2 nanosheets.

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