Facile synthesis of unique diamond-like structured CdMn^sub 2^O^sub 4^@CdMn2O4 composite material for high performance supercapacitors

In this work, we report a facile and cost-effective two-step hydrothermal method to fabricate the unique hierarchical CdMn2O4@CdMn2O4 structures on Ni foam for the first time. The CdMn2O4 diamond structures are fully covered on mesoporous CdMn2O4 nanoparticles. Compared with the bare CdMn2O4 nanoparticles, the composite CdMn2O4@CdMn2O4 electrode exhibits higher pseudocapacitive behaviors in 2 M KOH, which delivers a greatly enhanced specific capacitance of 3885 F g-1 at a current density of 1.5 A g-1. In addition, composite CdMn2O4@CdMn2O4 electrode shows superior cycling stability, retaining 99.8% of the initial capacitance after 2000 cycles at a current density of 5 A g-1.