Garnet-PEO composite solid electrolytes: a multiscale view on Li+ transport and electrodeposition properties

Fast expanding sector of mobile electronics and electric vehicles looks for new battery solutions to overcome limitations of commercially available liquid electrolyte. Solid electrolytes, such as ceramics and polymers have... [ view full abstract ]

Fast expanding sector of mobile electronics and electric vehicles looks for new battery solutions to overcome limitations of commercially available liquid electrolyte. Solid electrolytes, such as ceramics and polymers have been proposed to meet safety and energy density requirements in Li metal batteries. However, the poor stability of polymers in contact with metallic Li and the high interfacial resistance of ceramics are limiting the development of full solid state Li metal batteries. A promising approach is to combine desirable properties of ceramic and polymeric electrolytes into a composite electrolyte concept. In this contribution, we investigate the composite system based on PEO-LiTFSI polymeric matrix enriched with sub>6.55La₃Zr₂Ga_0.15O₁₂ garnet fillers, with the aim to overcome the limitations of ceramic electrolytes for practical application in Li metal based batteries. A new processing approach has been applied to ensure high structural homogeneity and reproducibility of composite membranes across a broad range of ceramic filler content. Electron microscopy and magnetic resonance techniques were used to locally characterize the structure of the composites. The Li local mobility was also investigated in detail to understand and propose possible transport mechanism. Impact of garnet filler content on the macroscopic Li-ion conductivity will be discussed as well as their influence on the polymer matrix stability with metallic Li anode.