화학공학소재연구정보센터
Electrochimica Acta, Vol.48, No.7, 867-874, 2003
Effects of pretreatment of natural graphite by oxidative solutions on its electrochemical performance as anode material
Modification of natural graphite has recently moved into the focus of methods to prepare anode materials for lithium ion batteries. Here we report a treatment method for the modification of a common natural graphite employing oxidative solutions. Four solutions based on H2O2, Ce(SO4)(2), HNO3 and (NH4)(2)S2O8 were employed; their effects were investigated with X-ray photoelectron spectroscopy, thermogravimmetric and differential thermal analysis, high resolution electron microscopy and measurement of electrochemical capacity. All oxidants resulted in marked improvements of reversible capacity, columbic efficiency in the first cycle and cycling behavior due to elimination of some imperfections with high activities towards lithium such as carbon chains, edge carbon atoms and sp(3)-hybridized carbon atoms, creation of more micropores/nano-channels, modification of the surface of natural graphite with a coverage of a dense layer of oxides, and improvement in stability of graphite structure. Effects of the oxidative solutions on electrochemical performance of natural graphite are compared.