リチウムイオン二次電池用負極材料における機械的損傷と電気化学的特性変化に関する研究

抄録

Silicon is a promising anode material for lithium-ion battery application due to its high specific capacity. However, when silicon is lithiated, it can undergo a volume expansion, which leads to an extensive fracturing. This is thought to be a primary cause of the rapid decay in cell capacity routinely observed.. To solve this problem, a more thorough understanding of how the material degrades is necessary to help cycling techniques that may be capable of reduce capacity fading. In this study, we report in situ acoustic emission in silicon negative electrodes. The largest number of emissions occurred on the first lithiation in silicon negative electrode. Two types of AE signal were identified by the FFT analysis. One type was emission from the silicon damages. The other was emission from the gas generation. AE of the gas generator has a peak of less than 100 kHz. In contrast, AE of silicon damage has a peak of more than 100 kHz. this study demonstrates that AE is a powerful tool to survey the real-time mechanical damage and electrochemical degradation in the electrode.