Preparation processes and properties of expanded graphite for alkaline batteries

Alkaline batteries have been produced by using expanded graphite as cell cathode conductive material. Expanded graphite was obtained by chemical (CI) and electrochemical (EI) intercalation processes and evaluated. Natural graphite was intercalated with H2SO4, washed, expanded, milled and characterized. Milled graphite was added to natural graphite (1:1 ratio) and tested as a conductive cathode material of high performance alkaline cells. Both processes resulted in suitable alkaline battery materials, however, the electrochemically intercalated samples tended to perform better than chemically intercalated did, because of their better textural characteristics. EI samples had better particle preservation and a larger amount of intercalate, which resulted in better expansion, higher porosity and larger specific surface area, and consequently, a better defoliation than that obtained in the milling process of CI samples.