Ultrathin nanosheet-assembled hollow microplate CoMoO4 array derived from metal-organic framework for supercapacitor with ultrahigh areal capacitance

The rational control of metal-organic frameworks derived hollow nanomaterials with rapid mass transport and multiple active metal sites are desirable for emerging energy storage. Herein, CoMoO4 hollow microplate array on Ni foam is prepared via a facile self-sacrificing templated strategy from ion-exchange of cobalt-organic framework microplate array. Benefiting from hollow microplate structure constructed by ultrathin nanosheets, CoMoO4 as binder-free electrode for supercapacitor delivers ultrahigh areal capacitance/capacity (12.2 F cm−2/6120 C cm−2 at 2 mA cm−2), superior rate property (82.2% at high current density of 50 mA cm−2) and excellent cycling stability (90.5% retention after 5000 cycles). Moreover, an asymmetric supercapacitor device is assembled by using CoMoO4 as positive electrode and activated carbon as negative electrode, achieving high energy density of 0.321 mWh cm−2 at power density of 1.7 mW cm−2 and superior capacitance retention of 96.0% over 5000 cycles. Importantly, a blue light-emitting diode can be illuminated 2 min, indicating a great potential for practical applications. These excellent results demonstrate that this efficient strategy can extend to prepare various bimetallic oxides arrays with hollow and hierarchical microstructure for high-performance supercapacitors.