NiCo₂S₄ nanosheet grafted SiO₂@C core-shelled spheres as a novel electrode for high performance supercapacitors

A high-performance supercapacitor electrode NiCo₂S₄ (NCS) nanosheet on SiO₂@C core-shell nanospheres (SiO₂@C-NCS nanocomposite) is prepared via simple an effective solution-based method. Benefiting from compositional and structural advantages, the as-prepared SiO₂@C-NCS nanocomposite exhibits a high specific capacitance (625 F g⁻¹ at 1 mA cm⁻²) and a stable cycling performance. An asymmetric supercapacitor (ASC) assembled with SiO₂@C-NCS nanocomposite as a positive electrode and carbon nanotube paper as a negative electrode in aqueous KOH solution demonstrated a high energy density of 16 Wh kg⁻¹ at an ultra-high specific power of 7200 W kg⁻¹. These promising results suggest the possible application of mixed transition metal sulfides-based composites as advanced electrode materials for high-performance ASCs. (paper)