固体電池を圧縮すると短絡を防止できる(Squeezing solid-state batteries prevents short-circuits)

2026-08-28 スタンフォード大学

スタンフォード大学とSLAC国立加速器研究所の研究者らは、全固体電池で問題となる短絡を、固体電解質への圧縮力を適切に制御することで防止できることを明らかにした。全固体リチウム金属電池では、充放電時にリチウムが固体電解質内部へ侵入して金属フィラメントを形成し、正負極をつないで短絡することが課題となっている。研究では、電池を圧縮すると固体電解質の亀裂やリチウム侵入の挙動が変化することを実験的に解析し、適切な圧力条件ではリチウムの異常な侵入を抑制できることを示した。これは、全固体電池の安全性・信頼性向上だけでなく、製造時に必要となる積層・加圧条件の最適化にもつながる成果である。

固体電池を圧縮すると短絡を防止できる(Squeezing solid-state batteries prevents short-circuits)
Compressed electrolyte showing horizontal dendrite propagation, which prevents short-circuiting. | Greg Stewart / SLAC National Accelerator Laboratory

<関連情報>

二軸応力下の固体電解質におけるデンドライトの発生と偏向 Dendrite initiation and deflection in biaxially stressed solid electrolytes

Teng Cui,Sunny Wang,Samuel S. Lee,Eddie Barks,John Cattermull,Celeste Melamed,Zhelong Jiang,Madison Morrison,Leah Narun,Yan-Kai Tzeng,Naoki Fujii,Seung Hyan Kim,Xin Xu,Geoff McConohy,Paul M. Wallace,Andrew C. Lee,Xiao Cui,Joon-Hyung Lee,William C. Chueh & X. Wendy Gu
Nature  Published:01 July 2026
DOI:https://doi.org/10.1038/s41586-026-10734-x

Abstract

Lithium-metal solid-state batteries offer advantages of high energy density and improved safety compared with lithium-ion batteries1,2. However, solid-state batteries fail through short-circuiting even at low charging rates (less than 1 mA cm2) due to lithium dendrite initiation and propagation3,4,5. The location of dendrite initiation is under debate, particularly regarding whether initiation occurs within the interior of the solid electrolyte6,7,8,9 or at the surface10,11,12,13,14. Here we develop an in-plane biaxial compression method that provides direct evidence that dendrite initiation occurs within the interior of garnet Li6.6La3Zr1.6Ta0.4O12 solid electrolytes during long-term cycling when the surface initiation mechanisms are rendered ineffective in shorting the cell. The biaxial compression deflects dendrite propagation so that it is perpendicular to the electric field direction, leading to the generation of an unprecedentedly high density of dendrites without short-circuiting, even at an extreme fast-charging rate of 100 mA cm2. After long-term cycling, dendrites eventually appeared throughout the entire thickness of the solid electrolyte. Under extreme cycling conditions, isolated lithium deposits are observed at grain-boundary junctions and pores, and these act as the dendrite initiation sites. This work reconciles the surface and interior initiation mechanisms in garnet solid electrolytes and demonstrates that in-plane biaxial compressive stress can prevent both from short-circuiting the cell.

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