Review on the critical issues for the realization of all-solid-state lithium metal batteries with garnet electrolyte: interfacial chemistry, dendrite growth, and critical current densities

All-solid-state battery is considered as the next generation of the energy storage system because of its improved safety and high-energy density compared to the conventional lithium-ion battery. Among different solid-state battery systems that have been studied, the garnet structured solid electrolyte based solid-state battery has attained tremendous research interest due to the highly advantageous intrinsic property of garnet solid electrolyte, especially high shear modulus, reasonable lithium-ion conductivity, wide electrochemical voltage window, and good stability with electrodes. However, the major hurdle in this battery system is the interfacial issues between lithium metal and lithium garnet solid electrolyte. In this review, we first summarize the recent progress in the garnet solid electrolytes, the origin of interface resistance between lithium metal and garnet solid electrolyte, lithium dendrite propagation in the garnet solid electrolyte, and the recent development in interfacial engineering. Also, we have briefly reviewed the "anode-free" structure for the lithium garnet-based all-solid-state battery and carefully analyzed its importance. We conclude this review with a few suggestions as a guide for future work.