-
The Perovskite Li3xLa2/3-xTiO3 (LLTO) has been investigated as a Li-ion solid electrolyte material and has attracted significant attention due to its wide operating voltage range. Polycrystalline and grain boundaries (GBs) are a common structural motif found in ceramic oxides. So, GBs can have a significant impact on the material properties. Here, we presented a molecular dynamics (MD) study that quantifies the effect of LLTO GBs on Li-ion transport. We examined six types of LLTO GBs, including P- Σ5(210), P-Σ5(310), P-Σ13(510) in the Li-poor phase and R-Σ5(210), R- Σ5(310), R-Σ13(510) in the Li-rich phase. We also consider LLTO bulk for comparison. The results show that the grain boundary formation energies of the six GBs are all below 1.30 J/m2, indicating the presence of a high concentration of GBs in polycrystalline LLTO. It is likely to find a highest concentration of Σ5(210) GB due to its lowest formation energy (1.00 J/m2 for P-Σ5(210) and 0.89 J/m2 for R-Σ5(210)). Compared with the bulk LLTO, Li+ in the six GBs exhibits a lower mean squared displacement (MSD), a smaller migration energy barrier and a lower ionic conductivity. These results confirm that LLTO GBs hinder Li+ transport. For bulk LLTO, the Li+ migration barrier is determined to be 0.30 eV (Li-poor phase) and 0.26 eV (Li-rich phase). In comparison, the migration barrier of LLTO GBs exhibits a slight decrease, ranging from 0.32 to 0.37 eV (Li-poor phase) and 0.27 to 0.31 eV (Li-rich phase). The computed Li-ion conductivities of the six GBs are 1 to 2 orders of magnitude lower than those of the corresponding bulk counterparts. Among the six GBs, P-Σ13(510) exhibits the highest Li+ conductivity of 4.76 × 10-5 S/cm in the Li-poor phase, whereas R-Σ5(310) shows the maximum Li+ conductivity of 1.31 × 10-3 S/cm in the Li-rich phase. Furthermore, the peak Li+ conductivity in the Li- rich phase is substantially higher than that in the Li-poor phase. In addition, Li+ transport perpendicular to the GB (i.e., from grain to grain) is more hindered relative to transport along the GB. Nevertheless, the Li+ diffusion can be improved by increasing the Li content within the GB region. The Li+ diffusion maps can be visualized by analyzing the Li+ trajectories of the MD simulations. We found that Li+ transport is restricted to the GB region first, then gradually turns to the bulk region, and finally forms a two-dimensional diffusion path similar to that of the LLTO bulk.Furthermore, the Li+ diffusion strongly depends on the distribution of O ions in LLTO GBs. For example, in the Li-poor-phase P-Σ5(310) GB, the number of O ions in the GB region is greater than that in the bulk region, which indicates a stronger Li-O attractive interaction in the GB region and so hinders Li+ transport towards the bulk region. Collectively, these atomic- scale insights deepen our understanding of LLTO GBs and their influence on Li+ transport.
-
Keywords:
- solid electrolytes /
- LLTO grain boundary /
- molecular 10 dynamics simulation /
- Li-ion transport
-
[1] Ma M M, Zhang M H, Jiang B T, Du Y, Hu B C, Sun C G 2023 Mater. Chem. Front. 7 1268
[2] J. Janek, W. G. Zeier 2016 Nat. Energy 500 300
[3] Manthiram A, Yu X W, Wang S F 2017 Nat. Rev. Mater. 2 1
[4] Wang Z Y, Wang T R, Zhang N, Zhang W R, Liu Y J, Wang C S 2025 Adv. Mater. 37 2501838
[5] Chen S, Gao Z, Sun T 2021 Energy Sci. Eng. 9 1647
[6] Li L, Duan H, Li J, Zhang L, Chen G 2021 Adv. Energy Mater. 11 2003154
[7] He X, Mo Y, Zhu Y 2016 J. Mater. Chem. A 4 3253
[8] Xu L, Feng T S, Huang J Q, Hu Y B, Zhang L F, Luo L L 2022 ACS Appl. Energy Mater. 5 3741
[9] Han F D, Westover A S, Yue J, Fan X L, Wang F, Chi M F, Leonard D N, Dudney N, Wang H, Wang C S 2019 Nat. Energy 4 187
[10] Oshiyuki I, Chen L Q, Mitsuru I, TetsurB N 1993 Solid State Commun. 86 689
[11] Chen C H, Amine K 2001 Solid State Ion. 144 51
[12] Symington A R, Molinari M, Dawson J A, Statham J M, Purton J, Canepa P, Parker S C 2021 J. Mater. Chem. A 9 6487
[13] Ren Y Y, Shen Y, Lin Y H, Nan C W 2015 Electrochem. Commun. 57 27
[14] Cheng E J, Sharafi A, Sakamoto J 2017 Electrochim. Acta 223 85
[15] Chen B B, Xu C Q, Zhou J Q 2018 J. Electrochem. Soc. 165 A3946
[16] Dawson J A, Canepa P, Famprikis T, Masquelier C, Islam M S 2018 J. Am. Chem. Soc. 140 362
[17] Yu S, Siegel D J 2018 ACS Appl. Mater. Interface 10 38151
[18] Sasano S, Ishikawa R, Kawahara K, Kimura T, Ikuhara Y H, Shibata N, Ikuhara Y 2020 Appl. Phys. Lett. 116
[19] Hua B, Sun B Z, Wang J X, Shi J, Xu B 2023 Acta Phys. Sin. 72 028201 (in Chinses) [华彪, 孙宝珍, 王靖轩, 石晶, 徐波 2023 物理学报 72 028201]
[20] Li M, Yan Y, Lan W X, Sun B Z, Wu M S, Xu B, Ouyang C Y 2025 Acta Phys. Sin. 74 088201 (in Chinese) [李梅, 严怡, 蓝雯欣, 孙宝珍, 吴木生, 徐波, 欧阳楚英 2025 物理学报 74 088201]
[21] Wang J X, Sun B Z, Li M, Wu M S, Xu B 2023 Chin. Phys. B 32 068201
[22] Davies P, Randle V 2013 Mater. Sci. Tech. 17 615
[23] Hirel P 2015 Comput. Phys. Commun. 197 212
[24] Sasano S, Ishikawa R, Sánchez-Santolino G, Ohta H, Shibata N, Ikuhara Y 2021 Nano letters 21 6282
[25] Catti M 2008 J. Phys. Chem. C 112 11068
[26] Qian D N, Xu B, Cho H M, Hatsukade T, Carroll K J, Meng Y S 2012 Chem. Mater. 24 2744
[27] Plimpton S 1995 Comput. Mater. Sci. 4 361
[28] Plimpton S 1995 J. Comput. Phys. 117 1
[29] Chen C H, Du J C, Chen L Q 2015 J. Am. Ceram. Soc. 98 534
[30] Symington A R, Molinari M, Statham J, Wu J, Parker S C 2019 J. Phys. Energy 1 042005
[31] Dawson J A, Tanaka I 2014 J. Phys. Chem. C 118 25765
Metrics
- Abstract views: 47
- PDF Downloads: 1
- Cited By: 0
下载:
