Shin, Ho Chul Nam, Kyung Wan Chang, Won Young Cho, Byung Won Yoon, Won-Sub Yang, Xiao-Qing Chung, Kyung Yoon 2024-01-20T18:00:34Z 2024-01-20T18:00:34Z 2021-09-02 2011-01-01 0013-4686 https://pubs.kist.re.kr/handle/201004/130739 The structural changes of LiFePO4 and C-coated LiFePO4 during charging at various C-rates and temperatures are investigated using synchrotron based in situ X-ray diffraction technique. The XRD patterns collected during cycling show the structural evidence of the positive effects of carbon coating on LiFePO4 for the electrochemical performance improvements at different temperatures, especially at low temperatures. At -10 degrees C, the C-coated LiFePO4 shows comparable capacities with the sample cycled at room temperature when cycled at C/5 rate with a slight shift of the plateau to a higher voltage during charging. The in situ XRD patterns collected simultaneously show a complete phase transformation from triphylite to heterosite. At -20 degrees C, the C-coated LiFePO4 delivers 55.6% of its theoretical capacities at C/5 rate. However, the plateau in the charging curve becomes sloppy and shifts to a higher voltage. The in situ XRD patterns show that the phase transformation from triphylite to heterosite is not completed when charged to 4.5 V due to the larger polarization when charged at -20 degrees C. (C) 2010 Elsevier Ltd. All rights reserved. English PERGAMON-ELSEVIER SCIENCE LTD LITHIUM BATTERIES PHOSPHO-OLIVINES ELECTRODES SPECTROSCOPY ABSORPTION LIXFEPO4 Comparative studies on C-coated and uncoated LiFePO4 cycling at various rates and temperatures using synchrotron based in situ X-ray diffraction Article 10.1016/j.electacta.2010.10.087 1 ELECTROCHIMICA ACTA, v.56, no.3, pp.1182 - 1189 ELECTROCHIMICA ACTA 56 3 1182 1189 scie scopus 000289225400025 2-s2.0-78650511777 Electrochemistry Electrochemistry Article LITHIUM BATTERIES PHOSPHO-OLIVINES ELECTRODES SPECTROSCOPY ABSORPTION LIXFEPO4 LiFePO4 In situ X-ray diffraction Low temperature performance Rate performance Lithium secondary batteries