Reconstruction of Co/Ni metal-organic-framework based electrode materials with excellent conductivity and integral stability via extended hydrothermal treatment toward improved performance of supercapacitors

Recently, although metal-organic-framework (MOF) had been widely used in the field of energy storage, their poor electronic conductivity and unstable structure limited their further application. In order to tackle these issues above, it is necessary to enhance the conductivity and stability of the MOF based electrode materials. Herein, reconstruction of bimetal Co/Ni metal-organic-framework (Co/Ni-MOF) based electrode materials with excellent conductivity and integral stability were achieved via a facile single-step hydrothermal process. In details, it was found that the part of Co/Ni-MOF can be transformed into graphite carbon and crystallized NiCo2O4 under the extended hydrothermal treatment. Through this strategy, the impedance of the electrode material had been significantly improved. The reconstructed electrode material was proved to exhibit an ultra-high specific capacity of 680.6 C g−1 at 1 A g−1 and great cycle stability. Moreover, the corresponding assembled asymmetric supercapacitor also demonstrated an outstanding performance. The maximum energy density of 79.6 Wh kg−1 could be achieved at a power density of 0.8 kW kg−1, and the 88.6 % initial capacity could be remained even after 5000 cycles. All in all, this work provided an optional route to modify the poor conductivity and tune the inferior integral stability of MOF-based electrode materials toward improved performance of supercapacitors.