Rational construction of MOF derived hollow leaf-like Ni/Co(VO3)x(OH)2-x for enhanced supercapacitor performance

Abstract

It is well known that the elements doping and morphology adjusting strategy are an effective ways to enhance the performance of supercapacitor electrode materials. In this work, using a Co-MOF as a precursor, a series of hollow-porous leaf-like V-doped nickel-cobalt layered double hydroxides (Ni-Co/V) nanosheets are successfully fabricated through a step-to-step etching process. The optimized Ni-Co/V-12-2 hollow leaf-like structure presents a typical hierarchical structure constructed by ultra-thin nanosheets and a hybrid pore of micro-/meso-porous with a BET surface area of 126.3 m2 g−1, which will provide the more active site and rich diffusion channels for enhanced energy storage performance. Therefore, the Ni-Co/V-12-2 electrode exhibits a high capacity of 161.4 mAh g−1 at 1 A g−1 and excellent cycle stability of maintaining 93.14% after 5600 cycles. Moreover, a hybrid supercapacitor with the Ni-Co/V-12-2 as the positive electrode and reduced graphene oxide (PPD/rGO) as the negative electrode, performs a high energy density of 55.22 Wh kg−1 at the power density of 0.375 kW kg−1.