Review—Microstructural Modification in Lithium Garnet Solid-State Electrolytes: Emerging Trends

Garnet structured solid electrolytes-based lithium metal batteries are the most attractive high energy density electrochemical energy storage candidates for the transportation and grid sectors. Various studies are carried out to address the concerns of lithium garnets as solid electrolytes and improve their electrochemical performance in lithium metal batteries. Interfacial engineering is a widely studied strategy for improving lithium garnet electrolyte-electrode interfacial contact and critical current densities. In the same perspective, microstructural/grain boundary engineering in lithium garnet is an effective strategy for overcoming obstacles and increasing critical current densities (CCD) in lithium metal battery research. The importance of the microstructural properties of the solid electrolyte has been discussed in several investigations. However, a comprehensive overview of the microstructural modification of lithium garnet solid electrolytes and their effect on electrochemical performance is still lacking. This review presents a detailed discussion on the strategies used to modify the microstructure and their impact on performances such as ionic conductivity, interfacial contact, critical current density, dendrite kinetics, etc., of lithium garnet ceramics.