Hierarchical Heterostructures of NiCo2O4@XMoO4 (X = Ni, Co) as an Electrode Material for High-Performance Supercapacitors

Hierarchical heterostructures of NiCo 2 O 4 @XMoO 4 (X = Ni, Co) were developed as an electrode material for supercapacitor with improved pseudocapacitive performance. Within these hierarchical heterostructures, the mesoporous NiCo 2 O 4 nanosheet arrays directly grown on the Ni foam can not only act as an excellent pseudocapacitive material but also serve as a hierarchical scaffold for growing NiMoO 4 or CoMoO 4 electroactive materials (nanosheets). The electrode made of NiCo 2 O 4 @NiMoO 4 presented a highest areal capacitance of 3.74 F/cm 2 at 2 mA/cm 2 , which was much higher than the electrodes made of NiCo 2 O 4 @CoMoO 4 (2.452 F/cm 2 ) and NiCo 2 O 4 (0.456 F/cm 2 ), respectively. Meanwhile, the NiCo 2 O 4 @NiMoO 4 electrode exhibited good rate capability. It suggested the potential of the hierarchical heterostructures of NiCo 2 O 4 @CoMoO 4 as an electrode material in supercapacitors.