Abstract: The petroleum coke produced by the delayed coking process serves as a typical raw material for the production of artificial graphite anode of lithium batteries. The amount of lithium intercalated in the petroleum cokes is strongly related to the graphitization degree of petroleum cokes. The Mering-Maire method is commonly used to calculate the graphitization degree, which is based on the prerequisite that the interplanar distance of crystal face (d₀₀₂) is lower than 0.344 0 nm. The calcined petroleum coke does not undergo the graphitization process, sod₀₀₂ is larger. If d₀₀₂＞0.344 0 nm, graphitization degree of calcined petroleum coke can not be estimated by this method. In this study, a B-value method was proposed based on three kinds of petroleum cokes A, B, C, whose d₀₀₂ values are all greater than 0.344 0 nm. The estimated graphitization degree for the petroleum cokes is 25.29%, 24.58% and 22.29%,respectively. The modification method of graphitization degree proposed in this study is in good agreement with Mering-Maire method.

Key words: interplanar distance, graphitization degree, Mering-Maire equation, B-value method