Fabrication of CoMo-layered double hydroxide@Co 2 MoO 4 nanosheets for enhancing the performance of asymmetric capacitors

As a new class of energy storage devices, supercapacitors (SCs) exhibit performance that falls between batteries and traditional capacitors. Ternary transition metal oxide CoMoO 4 materials possess abundant redox active sites, but their conductivity and cycle stability are unsatisfactory when utilized as electrodes for supercapacitors. Here, a nanostructured CoMo-layered double hydroxide (CoMo-LDH)@ Co 2 MoO 4 nanosheets is directly grown on nickel foam (NF) using a two-step hydrothermal method. The CoMo-LDH@Co 2 MoO 4 composite electrode exhibits a relatively high areal capacitance of 3672 mF cm −2 at 2 mA cm −2 and still retains 88.3% capacity at 20 mA cm −2. Furthermore, CoMo-LDH@Co 2 MoO 4 is utilized as the positive electrode to construct an asymmetric solid-state supercapacitors (ASC). The results proved that the CoMo-LDHs and Co 2 MoO 4 nanosheets offer a higher capacity because of the reversible redox reactions involving the movement of OH − ions during both charging and discharging processes.