Graphite and carbon powders for electrochemical applications

Graphite and carbon powders occur in many different forms and emanate from many different sources. A systematic classification is given based on the degree of crystallinity, from low-structured coke and coal products to macro-crystalline graphite and nanocarbons. In the family of ‘carbon black’ the highly conductive products acetylene black and PUREBLACK® Carbon are discussed. Graphite can be either natural or synthetic. Depending on the formation of the natural graphite, the morphology can vary from micro-crystalline to macro-crystalline. Expanded graphite is described as a chemically treated, extremely thin, flake graphite. Synthetic graphite products are classified as either primary material or secondary. The latter is defined as a byproduct of graphite component- and electrode-manufacturing. The characterization of graphite and carbons is also discussed. A very useful characterization tool – the ‘PSTP’ model (purity, structure, texture, particle size) – has been formalized. These four basic parameters determine most of the application parameters such as conductivity, lubricity and elasticity. The influence of these four basic parameters on the application properties is examined.