An all-solid-state Li-ion battery comprising a novel porous Si anode, NCM cathode, and an efficient polymer/clay solid electrolyte

• Applicant: Professor Dr. Rainer Adelung
• Subject Area: Synthesis and Properties of Functional Materials
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 546658628

The collaborative DFG project aims to advance All-Solid-State Lithium-Ion Batteries (ASSLIBs) for achieving high energy density, with a focus on fundamental research. National Taiwan University (NTU) and Christian-Albrechts-University (CAU) contribute their expertise, with NTU emphasizing engineering aspects and CAU delving into essential research questions. NTU's primary objectives involve developing an effective A-CEI coating for Ni-rich NCM cathodes compatible with PEO(/PVDF)-based Solid Polymer Electrolyte (SPE). This encompasses exploring liquid-mediated coating processes for an interlayer of LixMClyFz and investigating correlations between the amount of F-doping and the electrochemical properties of LixMClyFz solid electrolytes (SEs). Additionally, NTU aims to design PEO-based composite SPEs with clays as fillers, targeting room temperature Li-ion conductivity ≥1.0 mS/cm and high mechanical strength. The research questions include understanding the correlations between the amount of F-doping and the electrochemical properties of LixMClyFz SEs, as well as exploring how solvents interact with Ni-rich NCM cathodes and affect the crystallization mechanism of LixMClyFz. CAU's contributions focus on understanding the fundamentals of chemically and mechanically stable interfaces between P-Si and SPE and their creating. This involves characterizing the interface with and without mechanical interlocking over multiple cycles and studying the effect of chemical interface modulations on ionic contact resistivity and long-term stability. CAU also explores the plasticity of the lithiated anode, investigating how external stimuli influence the plasticity of the lithiated anode, interdependencies of initial porosity, C-rate, cell pressure, time, and temperature on geometrical changes of the Si anode, and the influence of the cycling protocol on long-term stability. Together, NTU and CAU collaboratively address research questions related to the rate-limiting mechanisms and interplay of ASSLIB components (NMC, PSE, P-Si), classification of degradation mechanisms and side reactions, and examination of aging phenomena, such as changes in crystallinity in the SPE, Si, and NMC. To tackle the research questions, emphasis is on operando analytics including measurements at the synchrotron. The overarching goal of the project is to contribute to the development of high-energy-density ASSLIBs, addressing safety concerns associated with traditional LIBs by replacing volatile organic liquid electrolytes with solid-state electrolytes, thereby advancing the field of energy storage technology.

• DFG Programme: Research Grants
• International Connection: Taiwan
• Partner Organisation: National Science and Technology Council (NSTC)
• Cooperation Partner: Professor Nae-Lih Wu, Ph.D.