ZIF-67 derived nickel cobalt sulfide hollow cages for high-performance supercapacitors

For supercapacitors, development of electrode materials with superior electrochemical performance is urgently needed. Herein, we synthesized novel nickel cobalt sulfide (NiCo2S4) hollow cages as electrode materials for supercapacitors. The NiCo2S4 hollow cages possess a hollow interior and mesoporous structure, which could shorten ion diffusion distance and provide plentiful electroactive sites. Thanks to the appealing structures, the NiCo2S4 hollow cages exhibit an appealing capacitance of 1382 F g−1 at 1 A g−1. Furthermore, asymmetric supercapacitors (ASCs) are fabricated with the synthesized NiCo2S4 and active carbon (AC) as electrodes. The ASC shows an energy density of 35.3 Wh kg−1 at a power density of 750 W kg−1 and an outstanding cycling stability of 79% retention after 10,000 cycles. The excellent performance of NiCo2S4 hollow cages makes them promising candidates in supercapacitors.