Authors: Yongseon Kim
Publish Date: 2013/03/06
Volume: 17, Issue: 7, Pages: 1961-1965
Abstract
The evolution of gas in lithium ion batteries LIBs was investigated The large amount of gas emission related to a charged cathode has been a critical issue because it causes deformation and performance degradation of LIBs This study examined the effect of free lithium compounds such as Li2CO3 or LiOH on gas generation which revealed several different features comparing with gas generation related to the cathode active materials themselves CO2 was the main gas generated chainstructured carbonate solvents such as dimethyl carbonate or ethyl methyl carbonate generated more gas than cyclicstructured ethylene carbonate and the gas generation did not occur without LiPF6 in the electrolyte solution These were found to be the main reason for the different gasgenerating behaviors between LiCoO2 LCO and LiNi085Co012Al003O2 NCA cathodes For LCO which has a very small amount of free lithium compounds on the surface the gas was generated mainly by a reaction between delithiated LCO itself and the electrolyte solution whereas a considerable amount of gas was generated by surface free lithium for NCA Therefore the removal of free lithium compounds is essential particularly for NCA to prevent the swelling of LIBs
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