Fabrication of a 3D Hierarchical Sandwich Co 9 S 8 /α-MnS@N-C@MoS 2 Nanowire Architectures as Advanced Electrode Material for High Performance Hybrid Supercapacitors.

Supercapacitors suffer from lack of energy density and impulse the energy density limit, so a new class of hybrid electrode materials with promising architectures is strongly desirable. Here, the rational design of a 3D hierarchical sandwich Co9 S8 /α-MnS@N-C@MoS2 nanowire architecture is achieved during the hydrothermal sulphurization reaction by the conversion of binary mesoporous metal oxide core to corresponding individual metal sulphides core along with the formation of outer metal sulphide shell at the same time. Benefiting from the 3D hierarchical sandwich architecture, Co9 S8 /α-MnS@N-C@MoS2 electrode exhibits enhanced electrochemical performance with high specific capacity/capacitance of 306 mA h g-1 /1938 F g-1 at 1 A g-1 , and excellent cycling stability with a specific capacity retention of 86.9% after 10 000 cycles at 10 A g-1 . Moreover, the fabricated asymmetric supercapacitor device using Co9 S8 /α-MnS@N-C@MoS2 as the positive electrode and nitrogen doped graphene as the negative electrode demonstrates high energy density of 64.2 Wh kg-1 at 729.2 W kg-1 , and a promising energy density of 23.5 Wh kg-1 is still attained at a high power density of 11 300 W kg-1 . The hybrid electrode with 3D hierarchical sandwich architecture promotes enhanced energy density with excellent cyclic stability for energy storage.