Elucidating the Impact of Li<sub>3</sub>InCl<sub>6</sub>-Coated LiNi<sub>0.8</sub>Co<sub>0.15</sub>Al<sub>0.05</sub>O<sub>2</sub> on the Electro-Chemo-Mechanics of Li<sub>6</sub>PS<sub>5</sub>Cl-Based Solid-State Batteries
Feng Jin, Laras Fadillah, Quoc Hung Nguyen, Torgeir Matre Sandvik, Yu Liu, Adrián García-Martín, Elena Salagre, E. G. Michel, Dragos Stoian, Kenneth P. Marshall, Wouter van Beek, Günther J. Redhammer, Mir Mehraj Ud Din, Daniel Rettenwander
Abstract
High Resolution Image Download MS PowerPoint Slide Li 6 PS 5 Cl has attracted significant attention due to its high Li-ion conductivity and processability, facilitating large-scale solid-state battery applications. However, when paired with high-voltage cathodes, it experiences adverse side reactions. Li 3 InCl 6 (LIC), known for its higher stability at high voltages and moderate Li-ion conductivity, is considered a catholyte to address the limitations of Li 6 PS 5 Cl. To extend the stability of Li 6 PS 5 Cl toward LiNi 0.8 Co 0.15 Al 0.05 O 2 (NCA), we applied nanocrystalline LIC as a 180 nm-thick protective coating in a core–shell-like fashion (LIC@NCA) via mechanofusion. Solid-state batteries with LIC@NCA allow an initial discharge specific capacity of 148 mA h/g at 0.1C and 80% capacity retention for 200 cycles at 0.2C with a cutoff voltage of 4.2 V (vs Li/Li + ), while cells without LIC coating suffers from low initial discharge capacity and poor retention. Using a wide spectrum of advanced characterization techniques, such as operando XRD, XPS, FIB-SEM, and TOF-SIMS, we reveal that the superior performance of solid-state batteries employing LIC@NCA is related to the suppression of detrimental interfacial reactions of NCA with Li 6 PS 5 Cl, delamination, and particle cracking compared to uncoated NCA.