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A Comparison of Formation Methods for Graphite//LiFePO 4 Cells
Author(s) -
Moretti Arianna,
Sharova Varvara,
Carvalho Diogo V.,
Boulineau Adrien,
Porcher Willy,
de Meatza Iratxe,
Passerini Stefano
Publication year - 2019
Publication title -
batteries and supercaps
Language(s) - English
Resource type - Journals
ISSN - 2566-6223
DOI - 10.1002/batt.201800109
Subject(s) - high resolution transmission electron microscopy , x ray photoelectron spectroscopy , graphite , electrolyte , materials science , electrochemistry , anode , lithium (medication) , chemical engineering , electrode , interphase , ion , nanotechnology , chemistry , transmission electron microscopy , composite material , medicine , organic chemistry , endocrinology , biology , engineering , genetics
The sequence of initial cycles necessary for the build‐up of the solid electrolyte interphase (SEI) on the anode surface of Li‐ion batteries (usually called formation) is a cost‐ and time‐consuming process, thus requiring further optimization. Herein, three different protocols are compared to explore possibilities to reduce the formation time of the cells without negatively affecting the electrochemical performance. XPS and HRTEM analyses are used to identify the main characteristics of the as formed SEIs. Electrochemical tests are conducted on full lithium‐ion cells using state‐of‐the‐art graphite and LiFePO 4 electrodes. The time‐saving dual‐current protocol results in excellent cycling performance, and in a LiF‐rich SEI. Interestingly, the use of moderately high temperature (40 °C) does not strongly affect the SEI composition as evidenced by XPS analysis. On the other hand, the formation rate determines the degree of graphite surface amorphization, visualized by HRTEM.