Advanced Surface and Microstructural Characterization of Natural Graphite Anodes for Lithium Ion Batteries

Journal Article · Wed Jan 01 00:00:00 EST 2014 · Carbon

DOI:https://doi.org/10.1016/j.carbon.2014.02.031· OSTI ID:1127369

Gallego, Nidia C ^[1]; Contescu, Cristian I ^[1]; Meyer, III, Harry M ^[1]; Howe, Jane Y ^[1]; Meisner, Roberta Ann ^[1]; Payzant, E Andrew ^[1]; Lance, Michael J ^[1]; Yoon, Steve ^[2]; Denlinger, Matthew ^[2]; Wood, III, David L ^[1]

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1. ORNL
2. A123 Systems, Inc.

Natural graphite powders were subjected to a series of thermal treatments in order to improve the anode irreversible capacity loss (ICL) and capacity retention during long-term cycling of lithium ion batteries. A baseline thermal treatment in inert Ar or N2 atmosphere was compared to cases with a proprietary additive to the furnace gas environment. This additive substantially altered the surface chemistry of the natural graphite powders and resulted in significantly improved long-term cycling performance of the lithium ion batteries over the commercial natural graphite baseline. Different heat-treatment temperatures were investigated ranging from 950-2900 C with the intent of achieving the desired long-term cycling performance with as low of a maximum temperature and thermal budget as possible. A detailed summary of the characterization data is also presented, which includes X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and temperature-programed desorption mass spectroscopy (TPD-MS). This characterization data was correlated to the observed capacity fade improvements over the course of long-term cycling at high charge-discharge rates in full lithium-ion coin cells. It is believed that the long-term performance improvements are a result of forming a more stable solid electrolyte interface (SEI) layer on the anode graphite surfaces, which is directly related to the surface chemistry modifications imparted by the proprietary gas environment during thermal treatment.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1127369
• Journal Information: Carbon, Vol. 72; ISSN 0008-6223
• Country of Publication: United States
• Language: English