Chemical interaction in the cathode half-element of lithium ion batteries

Chemical interactions in the cathode half-element of lithium ion batteries with LiCoO2 as cathode and 1.15 M ILiPF6, in mixture of al-kylcarbonates as electrolyte had been studied by using a number of calculation and experimental methods. It was found that the layer of chemical interactions products on the surface of LiCoO2 grains comprised LiF and LiPO3 and, also, CoF2, which passed to the electrolyte solution with time. Moreover, the LiCoO2 surface was covered with a layer of alkyl carbonate polymerization products. It was demonstrated that the performance of the batteries was impaired due to the mutual thermodynamic instability of LiCoO2 and LiPF6. The electron short-circuiting which was due to appearance of Соn+ ions in the electrolyte contributed most to the batteries degradation process.

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