Advanced surface and microstructural characterization of natural graphite anodes for lithium ion batteries

作者：Gallego Nidia C; Contescu Cristian I; Meyer Harry M III; Howe Jane Y; Meisner Roberta A; Payzant E Andrew; Lance Michael J; Yoon Sang Y; Denlinger Matthew; Wood David L III^*

来源：Carbon, 2014, 72: 393-401.

DOI：10.1016/j.carbon.2014.02.031

Natural graphite powders were subjected to a series Of thermal treatments to improve the anode irreversible capacity loss and capacity retention during long-term cycling of lithiumion batteries. A baseline thermal treatment in inert Ar or N-2 atmosphere was compared to cases with a proprietary additive to the furnace gas. This additive substantially altered the surface chemistry of the uncoated natural graphite powders and resulted in significantly improved long-term cycling performance of the lithium ion batteries over the commercial, carbon-coated natural graphite baseline. Different heat-treatment temperatures were investigated ranging from 950 to 2900 degrees C to achieve the desired long-term cycling performance with a significantly reduced thermal budget. A detailed summary of the characterization data is also presented, which includes X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, and temperature-programmed desorption-mass spectroscopy. 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 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.

• 出版日期2014-6