As Lithium-Ion Batteries (LIBs) becomes an essential part of the everyday life, fireproof electrolytes have become an important component of the next generation battery design without compromising the performance of the battery. Composite electrolytes (CEs), consist of polymer electrolytes with highly conducting ceramic particles are promising candidates to substitute currently commercialized LIBs with liquid electrolytes. So far, experiments with CEs have discovered positive and negative effect on the overall conductivity of the CEs in the presence of ceramic particles.^1–4 Therefore, exists the conflict weather the CEs are the solution to overcome the disadvantages of all-liquid and all-solid electrolytes.

In this work, a 2-Dimensional CE with a uniform ceramic particle size distribution is studied via continuum modeling. we analyze the effect of interface between polymer and ceramic particle on the overall conductivity and transference number of the CEs to guide experimentalist to fabricate these interfaces carefully. It is concluded that the interplay between ohmic resistance and polymer conductivity at the polymer and ceramic particle interfaces can explain the conflicts observed in the literature. The Ohmic resistance at the interface is a critical parameter that determines whether ceramic particles enhance the overall conductivity or not. Finally, CEs does meet the criteria of the conductivity and transference number requirement in order to use in the EVs.⁵

References:

(1) Cheng, S. H.-S.; He, K.-Q.; Liu, Y.; Zha, J.-W.; Kamruzzaman, M.; Ma, R. L.-W.; Dang, Z.-M.; Li, R. K. Y.; Chung, C. Y. Electrochemical Performance of All-Solid-State Lithium Batteries Using Inorganic Lithium Garnets Particulate Reinforced PEO/LiClO4 Electrolyte. Electrochimica Acta 2017, 253, 430–438.

(2) Zagórski, J.; López del Amo, J. M.; Cordill, M. J.; Aguesse, F.; Buannic, L.; Llordés, A. Garnet–Polymer Composite Electrolytes: New Insights on Local Li-Ion Dynamics and Electrodeposition Stability with Li Metal Anodes. ACS Appl. Energy Mater. 2019, 2 (3), 1734–1746.

(3) Bonilla, M. R.; García Daza, F. A.; Ranque, P.; Aguesse, F.; Carrasco, J.; Akhmatskaya, E. Unveiling Interfacial Li-Ion Dynamics in Li ₇ La ₃ Zr ₂ O ₁₂ /PEO(LiTFSI) Composite Polymer-Ceramic Solid Electrolytes for All-Solid-State Lithium Batteries. ACS Appl. Mater. Interfaces 2021, 13 (26), 30653–30667.

(4) Choi, J.-H.; Lee, C.-H.; Yu, J.-H.; Doh, C.-H.; Lee, S.-M. Enhancement of Ionic Conductivity of Composite Membranes for All-Solid-State Lithium Rechargeable Batteries Incorporating Tetragonal Li7La3Zr2O12 into a Polyethylene Oxide Matrix. J. Power Sources 2015, 274, 458–463.

(5) Kim, H.-K.; Srinivasan, V. Status and Targets for Polymer-Based Solid-State Batteries for Electric Vehicle Applications. J. Electrochem. Soc. 2020, 167 (13), 130520.