The MEET Hi‑EnD III project, funded by the German Federal Ministry of Education and Research under grant number 03XP0258A, ran from 1 November 2019 to 30 April 2023. Its aim was to advance lithium‑metal batteries (LMBs) toward higher energy density while ensuring safety and economic viability. The research was carried out mainly at the Westfälische Wilhelms‑Universität Münster, in close cooperation with the Forschungszentrum Jülich, RWTH Aachen, and the ExcellentBattery‑Zentrum Dresden. The project was organised within the BMBF competence cluster ExcellBattMat, with the Münster site acting as the scientific coordinator for the cluster’s Platform 1 on lithium‑metal batteries.

Technically, the work was divided into four interrelated work packages. In the first, new liquid electrolytes were designed and tested, including the development of gel‑electrolyte systems that improve interfacial stability. The second package focused on electrode formulation and structuring; here, silicon thin‑film anodes were optimised, and passive host structures were introduced to suppress dendrite growth. Experimental investigations revealed that pulse charging combined with these host structures significantly reduced dendritic protrusions, while the newly developed solid‑electrolyte interphase (SEI) models—both implicit and explicit—provided a deeper understanding of lithium deposition morphology.

The third package addressed modelling and simulation. Multiscale models were constructed, ranging from atomic‑scale transport phenomena to full‑cell behaviour. These models were validated against experimental data and used to predict dendrite evolution under various charging protocols. The fourth package tackled resource and cost analysis. Building on a bottom‑up process‑based cost model for high‑nickel NMC cathodes (CAMCost), a multi‑criteria site assessment for an NMC811 plant across the EU was performed. An integrated total‑cost model (CellEst 3.0) was then applied to silicon thin‑film anodes, enabling a comprehensive cost‑performance comparison of emerging electrode concepts.

A key outcome of the project was the successful transfer of a lithium extraction technique, originally developed for lithium‑ion batteries, to lithium‑metal cells. By optimizing solvent additives and operating parameters, the extraction efficiency of lithium from aged or defective cells was markedly improved, providing a foundation for safer storage and transport of spent batteries. Additionally, the modelling work yielded quantitative insights into dendrite suppression strategies, informing the design of next‑generation cell architectures.

Throughout the project, the Münster team coordinated cluster‑wide activities, organising kick‑off and final meetings, and maintaining regular online conferences to keep all partners aligned, especially during the COVID‑19 restrictions. The collaboration with the ExcellentBattery‑Zentrum Dresden was particularly strong in the cost‑analysis work, while the Jülich and Aachen partners contributed experimental expertise and theoretical modelling, respectively. The project’s outcomes are being disseminated through peer‑reviewed publications and conference presentations, and the developed models and cost tools are made available to the wider battery research community.

In summary, MEET Hi‑EnD III delivered significant advances in electrolyte chemistry, electrode design, dendrite‑suppression modelling, and economic assessment for lithium‑metal batteries. The collaborative framework, supported by BMBF funding, enabled a comprehensive approach that bridges laboratory research and industrial feasibility, positioning the project’s findings as a valuable resource for the future development of high‑energy, safe, and cost‑effective battery technologies.