High-Performance Asymmetric Supercapacitors Based on Monodisperse CuO@C Polyhedron Nanocomposites

摘要

Herein,CuO nanocrystals spatially embedded inside carbon polyhedron(CuO@C)derived via morphology-preserved transformation of metal-organic frameworks(MOFs)are utilized for high-performance asymmetric supercapacitors(SCs).Using a conventional MOF(several micrometers in size),pore-filling with polymer inside MOF(polymer@MOF)via vapor-phase polymerization(VPP)process was achieved that amount of polymer used for VPP can be readily adjusted to control the carbon content of CuO@C after thermolysis and subsequent oxidation processes.When monodisperse and nano-sized MOF is used for CuO@C(denoted as nCuO@C_l),it presents superior electrochemical performance because monodispersity and smaller size reduce interfacial resistance and promote mass-transport property,respectively.Asymmetric SC of nCuO@C_l with carbon sphere(CS)as a counter electrode presents excellent energy density of 55.47 Wh/kg and long-term stability of 88.7% at 5000 cycles,comparable to the best MO-based asymmetric SCs derived from MOFs.