2025-06-05 ジョージア工科大学
＜関連情報＞
- https://research.gatech.edu/new-metal-design-solid-state-batteries
- https://www.science.org/doi/10.1126/science.adt5229
固体リチウム電池における変形可能な二次相を用いた界面形態形成 Interface morphogenesis with a deformable secondary phase in solid-state lithium batteries
Sun Geun Yoon, Bairav S. Vishnugopi, Douglas Lars Nelson, Adrian Xiao Bin Yong, […] , and Matthew T. McDowell
Science Published:5 Jun 2025
DOI:https://doi.org/10.1126/science.adt5229
Editor’s summary
A challenge for lithium solid-state batteries is the formation of voids at the lithium-electrolyte interface as the battery is cycled because the loss of interfacial contact degrades battery performance. The typical solution to this problem is to apply a stack pressure to deform the lithium, but the pressures required become unfeasible. Yoon et al. eliminated the need for high pressure by alloying the lithium with up to 20% sodium (see the Perspective by Spencer-Jolly). Because the sodium is immiscible, it forms domains within the lithium microstructure. However, it is also a good conductor, so the accumulation at the solid electrolyte interface ensures good electrical contact but it will still move away from the interface as the lithium plates out during charging. —Marc S. Lavine
Abstract
The complex morphological evolution of lithium metal at the solid-state electrolyte interface limits performance of solid-state batteries, leading to inhomogeneous reactions and contact loss. Inspired by biological morphogenesis, we developed an interfacial self-regulation concept in which a deformable secondary phase dynamically aggregates at the interface in response to local electro-chemo-mechanical stimuli, enhancing contact. The stripping of a lithium electrode that contains 5 to 20 mole % electrochemically inactive sodium domains causes spontaneous sodium accumulation across the interface, with the sodium deforming to attain intimate electrical contact without blocking lithium transport. This process, characterized with operando x-ray tomography and electron microscopy, mitigates voiding and improves cycling at low stack pressures. The counterintuitive strategy of adding electrochemically inactive alkali metal to improve performance demonstrates the utility of interfacial self-regulation for solid-state batteries.
