High-temperature graphitization of coke and lithium storage properties of coke-based graphite

ABSTRACT

Coal-derived carbon material is considered as a high-quality raw material for artificial graphite. Herein, the demineralized coke was prepared by acid washing, and coke-based graphite samples were prepared by high-temperature graphitization (2000°C–2800°C). The electrochemical performance of coke-based graphite samples was investigated. It is found that the high-temperature graphitization of the coke is inhibited by demineralization treatment. The graphitization degree of graphitized samples decreased after demineralization treatment. The graphitization degree of the graphitized samples at 2800°C from the raw coke and the demineralized coke can reach 74.48% and 68.78%, respectively. Chemical predemineralization treatment can reduce the mesoporous structure and specific surface area of the product. Moreover, onion-like graphite microspheres are found in graphitized samples from the coke before and after demineralization treatment. The order degree of the raw coke graphitization sample is significantly reduced by extending the graphitization preservation time. The electrochemical test results show that the graphitized sample, e.g., CG-2400, from raw coke (without demineralized) has better comprehensive electrochemical performance. The reversible specific capacity is 301.1 mAh/g at 0.1 C (1 C = 372 mAh/g). After 150 cycles at 1 C, the reversible specific capacity reaches 160.1 mAh/g.

KEYWORDS:

• Coke-based graphite
• microstructure
• anode material
• electrochemical performance

Acknowledgements

The authors are very grateful for China’s 12th Five-Year National Science and Technology Support plan project (2014BAB01B02). The authors also appreciate the support from Shaanxi Coal-Qinling Basic Science Research Five-Year Action plan for follow-up research.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Credit authorship contribution statement

Lipeng Wang contributed to investigation, formal analysis, writing-original draft. Jianguo Yang contributed to investigation, formal analysis, conceptualization, and supervision. Zhiang Li and Chenxian Du contributed to investigation. Lipeng Wang, Chenxian Du, Zhiang Li, Yi Han and Jianguo Yang contributed to writing-reviewing and editing.

Additional information

Funding

The work was supported by the China’s 12th Five-Year National Science and Technology Support plan [2014BAB01B02].