Abstract: Graphite electrode was modified with different concentrations of sodium benzoate (C7H5O2Na) solutions for application as an anode material for lithium ion battery. The electrochemical characterization of graphite modified with sodium benzoate was carried out by galvanostatic charge/discharge test, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Results showed that the graphite modified with C7H5O2Na exhibits significantly better cycle efficiency and greater reversible capacity than original graphite, and the first reversible charge/discharge specific capacity of modified graphite anode approaches 293.9 mAh/g and 326.4 mAh/g at 0.5C, higher than that of untreated graphite. The reason is that electrolyte interface film formed on the graphite surface could hinder the graphite expansion and benefit Li+migration. Simultaneously, quantum chemistry method was cited for calculating the lowest-unoccupied (LUMO) and highest-occupied (HOMO) molecular orbital energies. All supporting surface analyses and electrochemical results demonstrated the optimum concentrations of C7H5O2Na modified graphite electrodes are 1wt%. Moreover, the effects of modified graphite electrodes on electrochemical properties of batteries also were discussed at elevated temperature and under the optimum C7H5O2Na concentration.
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2017, Vol. 31 
