Electrochemical performance of a novel surface modified spherical graphite as anode material for lithium ion batteries

Electrochemical performance of a new surface modified spherical graphite (SSG) as anode material for lithium ion batteries was investigated. The SSG powder was deposited on a copper current collector sheet with vapor grown carbon fiber (VGCF) as a conductor and poly(vinylidene fluoride) dissolved in N-methyl pyrrolidinone as a binder. The coated sheet was heat-dried, roll pressed and punched into ̃1 cm diameter disks, which were used as the working electrodes. SEM was performed along with a microscope JEOL. The results showed that the carbon coating was thin and not homogenous, which was due to the non-uniform surface of the natural graphite. It was also observed that the dispersion of conductive additive markedly influenced the cycling behavior. White deposits such as power reversible capacity and rapid capacity fade were also observed as a result of poor dispersion.