Structure and transport properties of Li7La3Zr2−0.75xAlxO12 superionic solid electrolytes

Oxide Electrolytes for Lithium Batteries

“…Al contamination from the crucibles may be the key aspect in stabilizing the cubic phase of LLZO . The substitution of Al in LLZO lattice was supported by several researches although the substituted site is still an open question . Alumina was believed to also act as a sintering aid in some cases, where it can not only increase the relative density of the sintered pellet but also form highly conductive phase in the grain boundaries, resulting in higher total ionic conductivity .…”

“…228 The substitution of Al in LLZO lattice was supported by several researches although the substituted site is still an open question. 205,[233][234][235] Alumina was believed to also act as a sintering aid in some cases, where it can not only increase the relative density of the sintered pellet but also form highly conductive phase in the grain boundaries, resulting in higher total ionic conductivity. 216,218,236 Ga may play a similar role as Al when being intentionally added in LLZO.…”

Preparation of Li7La3(Zr2−,Nb )O12 (x= 0–1.5) and Li3BO3/LiBO2 composites at low temperatures using a sol–gel process

“…The partial substitution of Ge [5](T s : 1200°C), Ta [6](T s : 1000°C), Y [7] (T s : 1200°C) or Nb [8,9](T s : 1150°C) for Zr in LLZO helps to increase the total Li-ion conductivity, reaching maxima around 8 × 10 −4 S cm −1 at 25°C, which is twice that of the undoped LLZO. The addition of Al in the LLZO produces stabilization of the cubic phase at lower calcination temperature of 1000°C [10,11]. Rangasamy and co-workers have reported that 0.204 mol Al is necessary to stabilize the cubic phase and Li-ion conductivity of 1 × 10 −4 S cm −1 (T s : 1000°C) at 25°C [11].…”

Achieving high performance for aluminum stabilized Li 7 La 3 Zr 2 O 12 solid electrolytes for all solid‐state Li‐ion batteries: A thermodynamic point of view

“…The presence of Li 2 O in Figures and was believed to be due to the well‐documented Li exclusion phenomenon during Al incorporation in cubic LLZO structure based on the reaction given below: Taking into account the discussions in our previous paper, cubic LLZO could host more Al within the structure in comparison to tetragonal LLZO . As a result of this, Li 2 O could be excluded from the LLZO lattice when high Al containing cubic LLZO phase formed as a consequence of the Li exclusion phenomenon presented in the reaction given in Equation .…”

“…16,17 The band at around 520 cm −1 was T 2g mode of Li 2 O and appeared first in the sample sintered at 1100°C. 18 The presence of Li 2 O in Figures 3 and 4 was believed to be due to the well-documented Li exclusion phenomenon during Al incorporation in cubic LLZO structure based on the reaction given below: 19 Li…”