High-performance asymmetric supercapacitor constructed by MOF-derived Mn-Ni-Co sulfide hollow cages and Typha pollen-derived carbon

Transition metal sulfide electrode materials have been widely studied in recent years, among which structural control is a terrific way to boost the electrochemical performance. Consequently, in this work, Mn-Ni-Co sulfide composites with a double-layer hollow cage structure were prepared by facile ion etching and hydrothermal vulcanization, and the inherent application value in the field of supercapacitors was verified. Due to the special double-layer hollow structure and the synergy between various metal elements, the prepared electrode material exhibited superior electrochemical performance: the specific capacity reached 2460 F g−1 at the current density of 1 A g−1 and maintained 81.1% even if the current was raised by 20 times. Then, Typha pollen-derived carbon was produced with salt (ZnCl2/FeCl3) activation in one-step calcination. With a Mn-Ni-Co sulfide cathode and a Typha pollen-derived carbon anode, a hybrid supercapacitor device was assembled in a solution of 6 M KOH, which exhibited a great energy density of 80.4 Wh kg−1 at 800 W kg−1 and retained outstanding long-term cycling capability of 78.5% specific capacity after 10,000 cycles. The experimental results exhibit that the prepared composites have non-negligible application feasibility in supercapacitors. In addition, the simple structure control and tunable components make the method easily extended to the preparation of other materials, which has unique reference value for the preparation of multi-metal composites in other fields such as batteries and catalysis.