Li2CO3 contamination in garnet solid electrolyte: Origins, impacts, and mitigation strategies

Abstract

With the advancement of the energy revolution, a transformative shift in energy development and utilization, all-solid-state lithium batteries (ASSLBs) have emerged as a focal point for next-generation energy storage devices. Garnet-type Li₇La₃Zr₂O₁₂ (LLZO) solid electrolyte attracted much attention due to high ionic conductivity and thermal stability. However, LLZO faces the problem of Li₂CO₃ contamination, which significantly reduces its ionic conductivity, safety and interface compatibility. This review systematically analyzes the negative effects of Li₂CO₃ on ion migration, lithium dendrite growth, and battery performance, while deeply explores its formation mechanism and influencing factors. Strategies to address Li₂CO₃ issues are discussed, including elemental doping to optimize material structure, surface coatings to shield reactive gases, and techniques to remove or convert Li₂CO₃ layer. Furthermore, the integration of Li₂CO₃ removal processes during the preparation of polymer/garnet composite electrolyte (PGE) is highlighted. Leveraging artificial intelligence (AI) for data-driven material optimization is also discussed, with significant potential for advancing doping strategies and coating design. Additionally, sensing technologies are anticipated to provide real-time data for the precise control and mitigation of Li₂CO₃ contamination, offering new avenues for the development of robust garnet-based solid electrolytes.