Abstract
The demand of battery grade graphite is rising significantly. Electro thermal purification is one of the ways to achieve 99.9+% purity of graphite flakes with minimal environmental burden. In this work, we present impurity analyses of graphite samples subjected to high temperature treatment in an argon atmosphere (2500°C and 2800°C) and compare results to values reported in literature. Furthermore, as an understanding of electrical resistivity with commercial graphite flakes is still one of the key knowledge gaps in electro thermal purification technology, in this work both 2-probe and 4-probe methods are used to measure resistivity of three different graphite flakes (i.e. jumbo, large and medium). It is observed that overall fixed bed resistivity is dependent on various parameters such as a) particle size, b) void fraction, c) inter particle contact resistance, d) electrode to particle contact resistance and e) particle orientation in a fixed bed. For instance, smaller particles have higher fixed bed resistivity. A mechanistic model for graphite flakes was developed to predict fixed bed resistivity.