Effectively constructed by the interior and interface coexisting design of cobalt‐doped NiFe2S4 nanosheets for high‐performance supercapacitors

Summary The doped metal materials/transitional metal sulfides have been regarded as unique superior‐efficient electrodes because of their high Faradic activities. Nevertheless, the aggregation limits and poorer rate performances critically hinder the supercapacitors (SCs). Herein, the interior and interface coexisting design of cobalt‐doped NiFe2S4 nano sheets on nickel foam (Co‐ NiFe2S4) was constructed and synthesized via a two‐step hydrothermal approach. The Co‐ NiFe2S4 served as the skeleton supports and conductive pathways and supplies plentifully coordination ions to block the aggregations and enhance the nanostructured stabilities. The results are auspicious: the electrodes showed quick ion and electron transportation rates and many electroactive surface regions, evidencing their superior electrochemical performances. Regarding the superiority in physical and chemical characterizations, the Co‐NiFe2S4 composite was attracted more attention than other SCs applications because of their suitable morphology for electron/ion transportations, safety, numerous redox‐active sites with varied oxidational states, lower‐cost with nontoxicity, and high charge‐discharge rates in electrochemical activities. Especially, the Co‐NiFe2S4 electrode demonstrated superior electrochemical performance of specific capacity of 1075.4 C g−1 (2329.6 F g−1) at 1 A g−1 and capacity retention of around 96.8% after 5000 long‐cycles at 3 A g−1. These results signify that the ternary construction, Co‐NiFe2S4 composite is a superior capacitor at higher stabilities with a very less loss in capacity retentions, which is a promising electrode as a nanomaterial for high‐performance SCs that could be applicable in the commercial field soon. The Co‐FeCo2O4 interior and interface coexisting design array fabricated by two‐step hydrothermal method for high‐performance asymmetric supercapacitors with high capacity with excellent stability.