Toward Combinatorial Characterization of LLZO-Based Solid Electrolyte Thin Films

As the needs for higher energy density, durability, and safety came out, all-solid-state-lithium batteries (ASSLBs) have been developed to replace liquid electrolytes with its separator. Solid electrolytes, in general are fabricated via solid-state-reactions, requiring a high temperature and pressure. Lithium Lanthanum Zirconium Oxide (LLZO) is a promising electrolyte candidate, which has been predominantly studied for its wide electrochemical window and high ionic conductivity. LLZO, at room temperature, shows a tetragonal phase, whose ionic conductivity (~ 10^-6 S/cm) is much lower than the high temperature cubic phase (10^-4 ~ 10^-3 S/cm). With some additives of metal dopants, the cubic structure of LLZO can be formed at low temperatures. Moreover, by implementing physical vapor deposition techniques, the processing temperature can further be lowered. In this work, we propose a combinatorial and high-throughput experiments to efficiently explore composition dependent phase formation and ionic conductivity of LLZO-based thin film electrolytes. A custom-built combinatorial measurement setup for ionic conductivity of thin films is proposed. By combining the technique with combinatorial synthesis of LLZO-based systems using magnetron sputter deposition, ionic conductivity and phase maps with respect to composition can be acquired. Some preliminary results of the combinatorial experiments will be presented.