Effect of mild oxidation of natural graphite (NG7) on anode-electrolyte thermal reactions

The effect of mild oxidation of natural graphite (NG7) and some other parameters on the reaction between a fully lithiated graphite anode (Li_xC₆, x= 1.0-1.1) and 1 M lithium hexafluoroarsenate in ethylene carbonate and diethyl carbonate electrolyte (1:2, v/v) were studied by differential scanning calorimetry (DSC). It was found that mild oxidation of the graphite suppressed the exothermic reaction of the fully lithiated anode with the electrolyte, most probably as a result of the formation of a more stable and chemically bonded solid electrolyte interphase. Separation and removal of the small graphite particles from the anode mixture suppressed this reaction further. It was also found that the copper current collector, the amount of electrolyte and binder as well as other parameters have a significant influence on the heat evolution as measured by DSC.