Core–shell Co11(HPO3)8(OH)6–Co3O4 hybrids for high-performance flexible all-solid-state asymmetric supercapacitors

• Core–shell Co11(HPO3)8(OH)6–Co3O4 hybrids are synthesized for the first time.
• The as-prepared device is assembled from core–shell Co11(HPO3)8(OH)6–Co3O4 and graphene.
• Asymmetric solid-state supercapacitors show high performance.

A novel core–shell structured Co11(HPO3)8(OH)6–Co3O4 hybrid material was synthesized in a hydrothermal condition from the microporous Co11(HPO3)8(OH)6 microrod precursor. Due to the unique nano/microstructures, the assembled asymmetric all-solid-state supercapacitor (Co11(HPO3)8(OH)6–Co3O4 and graphene) showed a high gravimetric specific capacitance of 1.84 F cm−3 at 0.5 mA cm−2 and an excellent cycling stability with only 1.3% ca decay after 3000 cycling. The device delivered a maximum power density of 105 mW cm−3 at a current density of 1.5 mA cm−2 and possessed a maximum volumetric energy density of 0.48 mW h cm−3 at a current density of 0.5 mA cm−2. The device also exhibited excellent flexibility.

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