Designing an asymmetric device based on graphene wrapped yolk-double shell NiGa2S4 hollow microspheres and graphene wrapped FeS2-FeSe2 core-shell cratered spheres with outstanding energy density

Herein, we present a new method to construct a graphene wrapped yolk-double shell NiGa2S4 hollow microsphere (GW@YDSNGSHM) as a cathode electrode and a graphene wrapped FeS2-FeSe2 core-shell cratered sphere (GW-FeS2-FeSe2-CSS) as an anode electrode to enhance the performance of asymmetric supercapacitors. The GW@YDSNGSHM electrode shows considerable improvement of electrochemical performance including small internal resistance, reversibility, rapid kinetics, exceptional durability, and a notable specific capacitance (SC) of 2868.4 F g(-1). The advancement in the performance of the GW-FeS2-FeSe2-CSS includes a good SC of 634.6 F g(-1) and preferable durability. An asymmetric supercapacitor composed of the GW@YDSNGSHM (cathode) and GW-FeS2-FeSe2-CSS (anode) was assembled and tested. The advanced device revealed a SC of 352.30 F g(-1) and an energy density (ED) of 158.53 W h kg(-1) at a power density (PD) of 2236.16 W kg(-1). This improved performance is related to the structural properties of both electrodes which can ensure promising potential for future generations of electronic devices.