Metastable Chloride Solid Electrolyte with High Formability for Rechargeable All-Solid-State Lithium Metal Batteries

• DOI: 10.1021/acsmaterialslett.0c00127
• Publication Date: 2020-06-23T18:25:06Z
• Authors: Naoto Tanibata; Shuta Takimoto; Koki Nakano; Hayami Takeda; Masanobu Nakayama; Hirofumi Sumi
• Keywords: Fast ion conductor

Dense solid electrolytes in all-solid-state Li batteries are expected to suppress dendrite phenomena that prevent the application of high-energy-density metal electrodes. However, voids and cracks sintered still permit short-circuiting due dendrites. This study aimed investigate with high formability which green compacts can Li+ ion migration energies, bulk moduli, energies above hull were comprehensively investigated using first-principles classical force field calculations as indicators for ionic conductivity, formability, thermodynamic stability. The 231 compounds containing Cl listed Materials Project database studied their polarizability weak Coulombic interaction ions. Among them, monoclinic LiAlCl4 (LAC, S.G.: P121/c1) was focused on, owing its low values all three indicators. A mechanochemical synthesis attempted prepare metastable phase, where ions occupy interstitial sites, not just original because computation energy suggested conductive pathways between sites. XRD 7Li-MAS NMR measurements indicated mechanochemically synthesized LAC possessed a host structure, while 2.5% occupied tetrahedral Impedance showed exhibited an conductivity 2.1 × 10–5 S cm–1, 20 times higher than conventional solid-state at room temperature. more one order magnitude garnet-type Li6.6La3Zr1.6Ta0.4O12 (LLZT), has been attractive body SEM observations distribution relaxation analysis dense large necking particles contributed minimal grain-boundary resistance (7.5%) total resistance, LLZT almost completely (99%). symmetric cells pellet good cycle performance without overvoltage increase 70 cycles current density 0.1 mA cm–2, short circuiting occurred 1st cells.