Oxidation processes on conducting carbon additives for lithium-ion batteries

The oxidation processes at the interface between different types of typical carbon additives for lithium-ion batteries and carbonates electrolyte above 5 V versus Li/Li were investigated. Depending on the nature and surface area of the carbon additive, the irreversible capacity during galvanostatic cycling between 2.75 and 5.25 V versus Li/Li could be as high as 700 mAh g (of carbon). In the potential region below 5 V versus Li/Li, high surface carbon additives also showed irreversible plateaus at about 4.1–4.2 and 4.6 V versus Li/Li. These plateaus disappeared after thermal treatments at or above 150 C in inert gas. The influence of the irreversible capacity of carbon additives on the overall performances of positive electrodes was discussed.