Core-shell NiCo2S4@C with three dimensional carbon frameworks for enhanced asymmetrical supercapacitor and lithium storage performance.

Transition-metal sulfides have been considered as promising candidates for electrochemical supercapacitor and lithium ion batteries. Unfortunately, the shortcomings including large volume change, low conductivity as well as severe structural exfoliation from conductive substrate or current collector inhibit their practical application. Herein, the hydrothermal and solvothermal approach are developed for the controllable synthesis of core-shell NiCo 2 S 4 @C with three dimensional carbon frameworks. As an asymmetric supercapacitor, the NiCo 2 S 4 @C/YP-50 F displays a high energy density of 46.7 Wh kg−1 at a power density of 0.8 kW kg−1 and the good cycling stability (∼110 % of the initial capacitance retention at 16 kW kg−1 over 2000 cycles). Furthermore, the NiCo 2 S 4 @C exhibits the specific capacity of 414 mAh g−1 after 500 cycles at 2000 mA g−1 when evaluated as anode for lithium ion batteries. The excellent performance can be ascribed to the core-shell structure and the three dimensional carbon frameworks. The synthetic approach can be extended to fabricate other high performance metal sulfides for energy storage. [Display omitted] • Core-shell NiCo 2 S 4 @C with three dimensional carbon framework is synthesized. • The 3D carbon framework maintains the structure integrity and improves the electrical conductivity. • The chemical bonds of Co-C/Ni-C inhibits the structural exfoliation from carbon. • The core-shell NiCo 2 S 4 @C exhibits excellent electrochemical performance. [ABSTRACT FROM AUTHOR]