High-performance supercapacitor based on MOF derived porous NiCo2O4 nanoparticle

Transition metal oxide is a promising candidate for future supercapacitors due to its pronounced electrical properties and low cost. Unfortunately, the poor cycle stability and low capacitance due to the small lattice spacing and strong volume expansion in dense transition metal oxide impede its practical applications seriously. Herein, a nanoporous electrode of metal oxide has been prepared via the solvothermal and subsequent calcination process of MOF-74 (MOF=metal-organic framework), which shows outstanding cycle reversibility, excellent capacitance. Because of large surface areas with a nanoporous structure which is beneficial to the ion transport and relief to volume expansion. Three samples with different divalent metals (MOF-74-Ni, MOF-74-NiCo 2 and MOF-74-Co) were prepared by hydrothermal method. After a facile annealing process, the NiO, NiCo 2 O 4 and Co 3 O 4 with the large surface area and porous structure were easily obtained and further the electrochemical properties were investigated. As a result, the NiCo 2 O 4 electrode exhibits obviously high specific capacity (684 F/g) and excellent cycling stability (86% retention after 3000 cycles) compared with the monometallic oxides.