Structural limitations for optimizing garnet-type solid electrolytes: a perspective

Abstract

Lithium ion batteries exhibit the highest energy densities of all battery types and are therefore an important technology for energy storage in every day life. Today's commercially available batteries employ organic polymer lithium conducting electrolytes, leading to multiple challenges and safety issues such as poor chemical stability, leakage and flammability. The next generation lithium ion batteries, namely all solid-state batteries, can overcome these limitations through employing a ceramic Li + conducting electrolyte. In the past decade, there has been a major focus on the structural and ionic transport properties of lithium-conducting garnets, and the extensive research efforts have led to a thorough understanding of the structure-property relationships in this class of materials. However, further improvement seems difficult due to structural limitations. The purpose of this Perspective article is to provide a brief structural overview of Li conducting garnets and the structural influence on the optimization of Li-ionic conductivities.

An ion redistributor for dendrite-free lithium metal anodes

“…S5). Ions are concentrated in the neighboring pores of the commercial PP separator due to the inert Li-ion conductivity of the PP separator ( 31 ). The pores in PP filled with liquid electrolytes are the only pathway for Li-ion migration.…”

Crystal chemistry of "Li7 La3 Zr2 O12" garnet doped with Al, Ga, and Fe: a short review on local structures as revealed by NMR and Mößbauer spectroscopy studies

“…Recent research along these lines has shown that certain Li-oxide garnets have the necessary high ionic conductivities, as well as chemical and physical properties, to be considered as potential electrolytes in solid-state batteries (e.g. reviews of Cussen, 2010;Ramzy & Thangadurai, 2010;Zeier, 2014;Thangadurai et al, 2014).…”

The Ab Initio Calculations on the Areal Specific Resistance of Li‐Metal/Li7La3Zr2O12 Interphase

“…The areal specific resistance (ASR) is investigated by ab initio calculations in this article, to predict the intrinsic ASR as lower limitation. Among the existing SEs including Li 3 N, [3] Na superionic conductor (NASICON), [4] perovskite, garnet, thio-γ -Li 3 PO 4 related system [5] (including glass and glass-ceramic states), thio-Li superionic conductor (LISICON), [6] and Li 10 GeP 2 S 12 , [7] garnet structured Li ionic conductors attract dominated interests in recent years [8,9] mainly owing to an absence of valence variant elements and a resulting higher electrochemical stability especially with Li metal anode. The first step is investigated by climbing image nudged elastic band (CI-NEB), resulting in barrier energy lower than 0.37 eV compared to experimental 0.34 eV of the garnet bulk phase.…”

“…As the flammable organic liquid electrolyte is the main case of the urgent safety problem, the solid electrolytes (SEs) without flammable organic small molecular liquid gradually attracts wide attention, including inorganic ceramic electrolytes and dry organic polymer electrolytes. Among the existing SEs including Li 3 N, [3] Na superionic conductor (NASICON), [4] perovskite, garnet, thio-γ -Li 3 PO 4 related system [5] (including glass and glass-ceramic states), thio-Li superionic conductor (LISICON), [6] and Li 10 GeP 2 S 12 , [7] garnet structured Li ionic conductors attract dominated interests in recent years [8,9] mainly owing to an absence of valence variant elements and a resulting higher electrochemical stability especially with Li metal anode. However, the lithium metal anode shows poor compatibility with traditional organic liquid electrolyte owing to a continuously evolving Li/electrolyte interface during charge/discharge.…”

“…Requirements on SEs include higher conductivity than 10 −4 S cm −1 at room temperature as the threshold for running a regular cell, [2] negligible electronic conductivity, wide electrochemical stability window, and high chemical and electrochemical stability with electrodes. Among the existing SEs including Li 3 N, [3] Na superionic conductor (NASICON), [4] perovskite, garnet, thio-γ -Li 3 PO 4 related system [5] (including glass and glass-ceramic states), thio-Li superionic conductor (LISICON), [6] and Li 10 GeP 2 S 12 , [7] garnet structured Li ionic conductors attract dominated interests in recent years [8,9] mainly owing to an absence of valence variant elements and a resulting higher electrochemical stability especially with Li metal anode.…”