摘要
A C/Ni composite was prepared via thermal decomposition of a nickel oleate complex at 700℃,yielding disperse Ni nanocrystals with an average size of 20 nm,encapsulated by carbon nanosheets as deduced from transmission electron microscopy(TEM)images and confirmed from X-ray photoelectron spectroscopy(XPS).Furthermore,the X-ray diffraction pattern revealed a good ordering of the carbon layers,forced by the Ni encapsulation to adopt a bending structure.Considering the close interaction between the graphitized framework and the metallic nanoparticles we have studied the properties of the composite as an anode for Li-ion batteries.Compared with other nanostructured synthetic carbons,this carbon composite has a low voltage hysteresis and a modest irreversible capacity value,properties that play a significant role in its behaviour as electrodes in full cell configuration.At moderate rate values,0.25 C,the electrode delivers an average capacity value around 723 mAh·g^−1 on cycling,among the highest values so far reported for this carbon type.At higher rate values,1 C,the average capacity values delivered by the cell on cycling decrease,around 205 mAh·g^−1,but it maintains good capacity retention,a coulombic efficiency close to 100%after the first cycles and recovery of the capacity values when the rate is restored from 3 to 0.1 C.
基金
Ministerio de Economíay Competitividad(No.MAT2017-87541-R)and Junta de Andalucía(Group FQM-175).F.J.S.
UCO for fellowship“Universidad de Córdoba.Becas Semillero de Investigación”.E.R.C.thanks to project RTI2018-099668-BC22 of Ministerio de Ciencia,Innovacióny Universidades
UMA18-FEDERJA-126 of Junta de Andalucía and FEDER funds.J.C.V.
Support from UCLM through the 2019-GRIN-27165 grant.
