Low-temperature densification of Al-doped Li₇La₃Zr₂O₁₂: a reliable and controllable synthesis of fast-ion conducting garnets

Abstract

A hybrid sol–gel solid-state procedure employing 3 h calcination at 1100 °C is used to produce fast-ion conducting Al-doped Li7La3Zr2O12.

Atomistic Insight into Ion Transport and Conductivity in Ga/Al-Substituted Li7La3Zr2O12 Solid Electrolytes

“…Indeed, Rettenwander et al indicated that while Ga-rich LLZO displayed denser microstructures with better connected grains and smaller pores,Al-rich LLZO lead simultaneously to more pronounced separation of grains and increased grain sizes. The difficulty of producing dense Al-substituted garnets has been previously reported, and new synthesis methods have been developed to overcome this problem 17,65,66.…”

Al-incorporation into Li7La3Zr2O12 solid electrolyte keeping stabilized cubic phase for all-solid-state Li batteries

“…The highly conductive cubic phase have reported that Al dopants play a key role as cubic-phase stabilizers by replacing lithium lattice sites (e.g. 24d, 48 g, and 96 h) [10,11,14,18,23,25] . Although the exact Al sites replacing Li sites are not experimentally clear, it seems quite certain that Al substitution could produce a stabilized cubic phase and provide fast Li-ion conduction.…”

“…Tetragonal phase peaks were also observed at approximately 57 °and 59 °in the XRD pattern of the Li 7-y La 3 Zr 2 O 12 , indicating that the cubic phase became unstable owing to the loss of Li during the sintering process at 10 0 0 °C [11] . However Al-LLZO retained a solid cubic phase except for the formation of La 2 Zr 2 O 7 [26] , since Shinawi et al reported that several secondary phases can act as cubic-phase stabilizers to improve Li-ion conductivity [23] . With the same point of view, Al incorporation might have influenced the structural formation of secondary phases in the samples.…”

“…The use of Al dopants as cubic-phase stabilizers by partially replacing Li sites (i.e., 24d tetrahedral, 48 g/96 h octahedral sites) have been considered [19][20][21][22] . Density functional theory (DFT) calculations revealed that the 24d sites are energetically more favorable for Al than the 48 g/96 g sites [23] . Because those 24d sites are joint sites of the Li-ion pathway, Al substitution would impede three-dimensional Li diffusion in the cubic phase.…”

Interfacial Ion‐Transport Mechanism of Li7(Al0.1)La3Zr2O12 Solid Electrolyte Modified by using a Spark Plasma Sintering Method

“…With the rapid development of energy‐utilizing converter cells, all‐solid‐state lithium‐ion batteries have been gradually replaced the traditional liquid lithium‐ion batteries because the application of solid electrolyte avoids the disadvantage of expansion or even explosion problems caused by liquid batteries . Solid electrolytes play a vital role in all‐solid‐state lithium‐ion batteries due to the electron‐blocking and ion‐conducting effects between the cathode and anode electrodes…”