2023-04-05 アルゴンヌ国立研究所(ANL)
研究者らは、リチウム金属電池の課題である膨張と物質の蓄積について理解を深めるために、動画像を調査した。これにより、アノード、カソード、セパレーターの動きを詳細に観察し、バッテリーが正常に機能するために必要な理想的な厚さを特定することができた。
リチウムメタルは高度に反応性があり、過剰な反応はバッテリーの性能に悪影響を与える可能性があるため、薄いインターフェース層がバッテリーの健康状態を保護する役割を果たすことがわかった。
＜関連情報＞
- https://www.anl.gov/article/tiny-movements-deep-inside-a-battery
- https://www.sciencedirect.com/science/article/pii/S0378775322012502?via%3Dihub
オペランドエネルギー分散型X線回折によるリチウム金属電池の電極集合体移動とリチウム化不均質性の可視化 Visualizing electrode assembly movement and lithiation heterogeneity in lithium-metal batteries using operando energy dispersive X-ray diffraction
Ilya A. Shkrob, Pavan Badami, John S. Okasinski, Marco-Tulio F. Rodrigues, Daniel P. Abraham
Journal of Power Sources Available online: 28 October 2022
DOI:https://doi.org/10.1016/j.jpowsour.2022.232273
Highlights
•Method developed to determine NMC811 lithiation along the cathode cross-section.
•Operando X-ray method determines electrode assembly movement during battery cycling.
•Cathode-separator assembly moves 3.4 mm/mAh during the Li-plating/stripping process.
•Irreversible drift of the cathode-separator assembly is 11.3 mm/cycle.
•Cathode gradients are minimal during charge but noticeable during discharge.
Abstract
There is renewed interest in Li-metal anodes in order to increase the energy density of battery cells. Here, we demonstrate an operando X-ray crystallography method to visualize lithiation gradients and electrode assembly movement during electrochemical cycling of a Li-metal cell containing a Ni–Mn–Co layered oxide cathode (NMC811). During charge, deposition of Li+ ions from the cathode increases the Li foil thickness; during discharge, the thickness decreases as Li+ ions are stripped off the foil. The resulting periodic movement is observed through tracking of Bragg peaks from the ordered phases of the cathode and separator. In addition to this 3.6 μm/mAh displacement, continuous mossy Li build-up on the anode causes an irreversible drift of the assembly, which is ∼11.3 μm/cycle. Furthermore, our data indicate significant lithiation gradients in the NMC811 cathode during the oxide relithiation, which is not observed during the delithiation.
