Thin-film technology for flexible sulfide-based all-solid-state lithium batteries
Glasses and Ceramics (V&C) team
Abstract
Flexible all-solid-state lithium metal batteries (ASSLMBs) hold great promise for powering wearable electronics, yet their practical development is limited by several critical issues, such as the poor formability of sulfide electrolytes into thin separator, sluggish ion/electron transport in the cathode, and lithium dendrite growth at the anode. In this work, corresponding solutions were proposed for the aforementioned three key issues, and a systematic study was conducted on the effectiveness of these solutions. A Li3PS4 sol was synthesized and processed via spin-coating and spray-printing, where transient solvent-assisted nanoparticle sintering enabled pressure-free densification at 250 °C, yielding ultrathin films with an even thickness of 1~2.5 μm an ionic conductivity of ~10⁻⁵ S cm⁻¹. The ion-transport ability of these films was further validated in lithium deposition tests. Spray-printing was then employed to fabricate flexible Li2S composite cathodes, in which Li3PS4 nanoparticles acted as ion-conductive binders while carbon nanotubes established efficient mixed-conduction pathways and mitigated cycling-induced stress. The resulting cells exhibited stable cycling for 300 cycles at 0.1 C with a retained capacity of 840 mAh g−1Li2S. Furthermore, a Li-Ag-alloy & PEO hybrid interlayer was introduced at the Li anode/electrolyte interface, where PEO improved interfacial contact and Li–Ag alloy guided uniform lithium deposition and accommodated electroplating-induced stress. Combining these improvements, flexible Li-Li2S solid-state batteries were assembled, which cycled stably for 110 cycles without external stack pressure, maintaining a specific capacity of 720 mAh g−1Li2S . This work highlights synergistic advances in ultrathin electrolytes, flexible cathodes, and dendrite-free lithium anode, providing new design insights for flexible sulfide-based thin film lithium metal batteries.
Jury
Qun LUO, SINANO, Chinese Academy of Sciences, China/ Reporter
Frédéric LE CRAS, Research Director, CEA LITEN, France/Reporter
Jean-Noël CHOTARD, Associate Professor, University of Picardie, Amiens /Examiner
David LE COQ, Professor, University of Rennes, ISCR / Examiner
Laurent CALVEZ, Professor, University of Rennes, ISCR / PhD Director
Invited
Bo FAN, Associate Professor, University of Shenzhen
Contacts
Laurent Calvez, laurent.calvez@univ-rennes.fr
Lilin Wu, lilin.wu@univ-rennes.fr
