Designed synthesis of yolk-shelled NiCo2O4/MnCo2O4 hollow sphere with boosted performance for supercapacitors

Rational construct the micro architecture of electrode materials is verified as a feasible strategy for advancing the performance. Herein, controllable design of NiCo2O4/MnCo2O4 yolk-shelled hollow sphere from Ni-Mn-Co glycerate is presented via etching and calcination methods. For comparison, utilizing the Ni-Mn-Co glycerate, NiCo2O4/MnCo2O4 hollow and solid sphere are also achieved. Due to its distinctive textural with high surface area and mesoporous, the NiCo2O4/MnCo2O4 yolk-shelled hollow sphere possesses a large specific capacitance (1636F g-1 at 4.0 A g-1) and cycling durability (10 % reduction over 6000 cycles at 15 A g-1) in comparison with hollow and solid structures. In-depth evaluating the practical application for supercapacitor, a solid-state asymmetric supercapacitor is designed with NiCo2O4/MnCo2O4 yolk-shelled hollow sphere and active carbon. An energy density of 62.8 Wh kg- 1 is obtained at 1650.4 W kg -1, while retaining 23.2 Wh kg- 1 even in larger 12367.7 W kg -1. These results reveal that the NiCo2O4/MnCo2O4 yolk-shelled hollow sphere is a promotion material for supercapacitor. This work is expected to be promoted the synthesis of hollow structured hybrid ternary oxides, which are regard as latent candidates for energy storage.