[Analysis Case] Evaluation of Degradation of Lithium-Ion Secondary Battery Anodes

Consistent evaluation from battery cell manufacturing, degradation testing, disassembly, to investigation of state changes due to degradation.

A degradation test was conducted on a battery cell made with LiCoO2 as the positive electrode, graphite as the negative electrode, and LiPF6/EC:DEC as the electrolyte, which was left in a constant temperature chamber at 60°C in a charged state of 4.2V for about one week. After that, the cell was disassembled and cleaned in an Ar atmosphere, and TOF-SIMS analysis of the negative electrode graphite was performed. Before the test, fragments derived from the binder and electrolyte salt were confirmed, and after the test, fragments such as Li3PO4 and PF3O, which are believed to have been generated due to the degradation of the electrolyte salt, as well as fragments from Li2CO3, were observed. Additionally, the detection of Co suggests the possibility of leaching of the positive electrode active material.

Contract AnalysisContract measurement