The future of sustainable lithium-ion batteries: Ecodesign recommendations for solid-state technologies

The development of fourth-generation lithium-ion batteries with solid-state electrolytes represents a critical advancement for electric mobility. The early stage of solid-state battery (SSB) technology development, where material selection, cell architecture, and production processes are not yet fully defined, offers a critical opportunity to embed sustainability considerations directly into design choices. This study presents an ecodesign framework triangulating scientific literature, regulatory requirements, and battery expert interviews to generate validated recommendations for SSBs. The findings from 49 studies and interviews with seven expert research entities identified the Li-M anode and SSE as the primary environmental and cost hotspots, with cobalt in high-cobalt cathode chemistries also representing a critical social hotspot across the battery value chain. A total of 15 key sustainability parameters for SSB ecodesign were identified, from which 25 ecodesign recommendations were developed, considering the battery life cycle. Most recommendations cover materials and cell manufacturing. The most impactful recommendations include real-time digital monitoring tools that address the widest range of sustainability parameters by directly controlling Li-M anode plating losses and SSE uniformity, and module and pack integration for first-life extension. Cobalt reduction in cathode active materials, standardised cell formats, and closed-loop material flows between producers and recyclers also emerged as key recommendations, reflecting the material, performance, and end-of-life trade-offs identified in this study. As SSB technology approaches commercial scale, the identified hotspots and trade-offs provide a robust foundation for guiding research and development decisions toward more resource-efficient and sustainable battery technologies.