Purification and carbon-film-coating of natural graphite as anode materials for Li-ion batteries

• Published in: Electrochimica acta Vol. 52; no. 19; pp. 6006 - 6011
• Main Authors: Zhao, Haipeng, Ren, Jianguo, He, Xiangming, Li, Jianjun, Jiang, Changyin, Wan, Chunrong
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.05.2007; Elsevier
• Subjects: Applied sciences; Coating; Concentrated acid; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Exact sciences and technology; Lithium ion battery; Natural graphite; Oxidization; Resorcinol–formaldehyde; Natural graphite; Lithium ion battery; Resorcinol–formaldehyde; Oxidization; Coating; Concentrated acid; Heat treatment; Anode; Resorcinol-formaldehyde; Electrode material; Discharge charge cycle; Acidic solution; Thin film; Surface structure; Phenoplasts; Raman spectrometry; Electrical characteristic; Modified material; Concentrated solution; Scanning electron microscopy; Coating material; Secondary cell; X ray diffraction; Surface treatment; Chemical treatment; Morphology; Lithion ion batteries
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2007.03.050

A process of modification of natural graphite materials as anode for lithium ion batteries was attempted. The process started with the treatment of natural graphite with concentrated hydrochloric acid and concentrated sulfuric acid in a thermal autoclave, followed by the in situ polymerization of resorcinol–formaldehyde resin to coat the graphite, then heat-treatment. SEM, XRD, Raman and electrochemical charge–discharge analysis showed that the surface defects and impurities on natural graphite were eliminated by purification of the concentrated acids, and carbon-film encapsulation modified the surface structure of the graphite and reduced its BET surface area. The as-obtained natural graphite sample presented an initial charge–discharge coulombic efficiency of 88.4% and a reversible capacity of 355.8 mAh g −1. The proposed process paves a way to prepare a promising anode material with excellent performance with low cost of natural graphite for rechargeable lithium ion batteries.