Rational fabrication and optimized design of hierarchical Ni3S2-MOF electrodes for enhanced electrochemical energy storage

Abstract

How to design and synthesize of advanced MOF-based electrode materials for high-performance supercapacitors is still a huge challenge, herein, CoNi-MOF@Ni3S2 and ZIF-67/Ni3S2 with unique heterostructures are rationally designed and constructed. The composite electrode materials not only make up for the poor conductivity of MOF, but also improve the structural stability of Ni3S2. As expected, the optimized ZIF-67/Ni3S2 and CoNi-MOF@Ni3S2 electrode demonstrates a remarkably enhanced specific capacitance of 1017.13 F g−1 and 1930.04 F g−1 at 1 A g−1, respectively, which are higher than those of their respective monomeric components. Finally, ZIF-67/Ni3S2//AC and CoNi-MOF@Ni3S2//AC devices were assembled, which delivered an impressive energy density of 94.49 and 125.34 Wh kg−1, along with the corresponding power density of 966.34 W kg−1 971.86 W kg−1, respectively. Moreover, by comparison, the CoNi-MOF@Ni3S2 electrode material exhibits better supercapacitor performance than ZIF-67/Ni3S2. This effective protective strategy provides an alternative way for constructing MOF or sulfide electrodes with remarkably improved energy storage performance.