Three-dimensional microsphere-like cobalt-glycerolate strutted nickel hydroxidenitrate nanoflakes grown by hydrothermal method for asymmetric hybrid supercapacitors

The core-shell structure is always a greatly effective structure in asymmetric hybrid supercapacitor , duo to a high specific surface area and porosity that can accommodate partial expansion during the redox reaction. Herein, a cobalt-glycerolate@nickel hydroxidenitrate microsphere (CoG@Ni 3 (NO 3 ) 2 ·(OH) 4 ) with core-shell structure is prepared by a simple two-step hydrothermal method . The as-produced CoG@Ni 3 (NO 3 ) 2 ·(OH) 4 possesses extremely high specific capacity (265.9 mA h g −1 at 1 A g −1 ) and an excellent rate capability (with 75.5% of initial capacity at 10 A g −1 ). In addition, as an cathode material, flower-sphere-like Bi-Bi 2 Se 3 materials is selected to match a new CoG@Ni 3 (NO 3 ) 2 ·(OH) 4 //Bi-Bi 2 Se 3 asymmetric supercapacitor. It exhibits a specific capacity (125.1 mA h g −1 at 1 A g −1 ) and an impressive rate property (with 77.6% of initial capacity at 10 A g −1 ). Satisfactorily, the asymmetric supercapacitor device, which cleverly assembles by the above two electrode materials, achieves impressive specific energy of 54 Wh kg −1 at 760 W kg −1 , and a capacitance retention rate of 80% after 4000 cycles. The excellent performance of the asymmetric supercapacitor proves that the materials possess great potential in the energy storage field.