Hierarchical core-shell NiCoSe2@nickel cobalt layered double hydroxide nanocomposite as high-performance electrode materials for asymmetric supercapacitors

As an efficient energy storage device, supercapacitors have exhibited excellent charge storage capacity and stable cycling performance. However, the lower energy density makes it difficult to meet the performance requirements in practical applications. Here, a core-shell structure of NiCoSe2@NiCo-LDH was synthesized on carbon cloth by a two-step method. The NiCoSe2@NiCo-LDH composite as electrode of supercapacitor exhibited a specific capacitance of 2609.1 mF cm(-2) (1242.4F g(-1)) in three-electrode system, which was far higher than that of the NiCoSe2 electrode material, maintaining 85 % of the original capacity after 2000 cycles. The NiCoSe2@NiCo-LDH and activated carbon materials were further assembled to an asymmetric supercapacitor to verify their performance of real applications. The device exhibited a specific capacity of 912.5 mF cm(-2) at a current density of 2 mA cm(-2) and maintained 96.19 % of its original capacity after 2000 cycles, demonstrating its application potential.