2D@3D MoS2@Ni/Co-S submicroboxes derived from prussian blue analogues for high performance supercapacitors

Abstract

Tuning the morphology and structure at micro/nanoscale has become essential for the advancement of electrode materials for supercapacitors. Here, Ni-Co prussian blue analogue (PBA) is used as precursor and template to synthesize 3D hollow submicroboxes coated with 2D MoS2 nanosheets (MoS2 @Ni/Co-S) by one-pot solvothermal process. The study shows that the cubic voids in Ni-Co PBA submicrocubes become larger with the prolonging of solvothermal time owing to the etching reactions for Ni-Co PBA submicrocubes. MoS2 @Ni/Co-S synthesized at 200 ℃ for 20 h possesses typical hollow structure, which is a multi-component active material composed of MoS2, CoS, NiS, Co and Ni, and exhibits high specific capacity of 109.8 mAh g−1 at 1 A g−1 and superior rate capability with 75.4% capacity retention at 20 A g−1, the energy density of the assembled asymmetric supercapacitor is as high as 38.5 Wh kg−1 and the device shows excellent cycling stability of 85.4% after 5000 cycles. More importantly, this work not only offers an attractive strategy to combine Ni-Co PBA and classical solvothermal process, but also provides a new insight into the design of PBAs for advanced energy materials.