Assemble from 0D to 3D: anchored 0D molybdenum carbide on 3D octahedral amorphous carbon with excellent capacitive properties

Abstract

Molybdenum carbide (Mo2C) is an attractive candidate as the electrode active material of supercapacitors (SCs) due to its low cost, outstanding electrical conductivity and superior chemical stability; however, the aggregation of Mo2C nanoparticles impedes its applications. Herein, zero-dimensional (0D) Mo2C nanoparticles are anchored on three-dimensional (3D) octahedral amorphous carbon (3DPO-Mo2C/C) by a mild and effective method with carbonizing and etching the Cu/Mo-based metal–organic framework. The 3DPO-Mo2C/C displays a large specific surface area, abundant mesopores and stable 3D structure, which not only expose more active reaction sites and shorten diffusion paths for electrolyte ions, but also prevent the aggregation and improve the structure stability of Mo2C nanoparticles. It exhibits an outstanding specific capacitances of 110 and 105 F g−1 in the electrolytes of 6 M KOH and 2 M EMIMA/AN. Employing the active carbon (AC) as counter electrode to assemble a SC with 3DPO-Mo2C/C as work electrode, which delivers higher energy and power densities of 12 Wh kg−1 and 1620 W kg−1, and the specific capacitance remains 91.3% after 6000 cycles. This approach not only prevents the aggregation of Mo2C nanoparticles successfully but also provides a possibility for Mo2C to be used in SCs.