Engineering robust interfaces for enhanced Li metal and ceramic electrolyte compatibility in solid-state systems

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2024-12, Vol.502, Article 158175
• Main Authors: Lee, Rae-Hyun, Jo, Ha-Na, Kang, Chea-Yun, Lee, Jong-Kyu, Kim, Hyun-Soo, Jin, Bong-Soo, Kim, Kyong-Nam, Yoon, Jung-Rag, Lee, Seung-Hwan
• Format: Article
• Language: English
• Subjects: Li-ion transference number; Li2O-B2O3-Al2O3; Long-term cycling performance; Oxide ceramic electrolytes; Polymer/ceramic/polymer sandwich-type electrolyte
• ISSN: 1385-8947
• DOI: 10.1016/j.cej.2024.158175

•Electrochemical performance of Li₂O-B₂O₃-Al₂O₃ electrolyte was improved using a sintering additive.•Ionic and electronic conductivity strongly depends on grain-boundary chemistry.•Poor interfacial contact of Li₂O-B₂O₃-Al₂O₃ oxide electrolyte was resolved with polymer electrolyte integration.•Polymer/ceramic/polymer sandwich electrolytes address issues by integrating the benefits of each layer. Oxide ceramic electrolytes shed light on the field of solid-state electrolytes. Here, we propose a Li2O-B2O3-Al2O3 (LBA) oxide ceramic electrolyte, which has low sintering temperature of 520 °C. Moreover, we introduce aluminum nitrate (AlN) as a sintering aid to optimize the grain boundary structure and chemistry through the liquid-phase sintering method. Currently, the main technical challenge with the oxide ceramic electrolytes is the high interfacial resistance at the electrolyte/electrode interface. Hence, we show that a polymer/ceramic/polymer sandwich-type electrolyte (PCPSE) to solve the interfacial issue of ceramic electrolytes. Notably, PCPSE alleviates the electric double layer at the electrolyte/electrode interface by blocking anionic transfer, due to extremely high Li+ transfer number of ceramic electrolytes. The polymer outer layer enhances physical contact with electrode and uniform Li+ diffusion at the interface. This sandwich architecture integrates the benefits of both polymer and ceramic electrolytes. Taken together, all-solid state Li/PCPSE/LiFePO4 batteries demonstrates stable long-term cycling performance with a high Coulombic efficiency of 99.8 % over 100 cycles.