(376o) First-Principles Study on Developing Li10-XSnP2S12-XClx Electrolyte with Outstanding Li-Ion Conductivity for High-Voltage Solid State Batteries
AIChE Annual Meeting
2019
2019 AIChE Annual Meeting
Computational Molecular Science and Engineering Forum
Poster Session: Computational Molecular Science and Engineering Forum (CoMSEF)
Tuesday, November 12, 2019 - 3:30pm to 5:00pm
First-Principles Study on
Developing Li10-xSnP2S12-xClx Electrolyte
with Outstanding Li-ion Conductivity for High-Voltage Solid State Batteries
Kyungju
Nam1, Jeemin Hwang2, Byungchan Han1,2,*
1
Department of Vehicle Convergence Engineering, Yonsei University, Seoul 03722,
Republic of Korea
2
Department of Chemical and Biomolecular Engineering, Yonsei University, Seoul
03722, Republic of Korea
Using
first-principles density functional theory calculations (DFT) and ab-initio
molecular dynamics (AIMD) simulations, we suggest Li10-xSnP2S12-xClx
(LSPSC) for the first time as solid electrolyte with supreme ionic conductivity:
the substitution of Sn4+ for Ge4+ and the partial
substitution of Cl- for S2- to a Li10GeP2S12
(LGPS) electrolyte which is well-known sulfide electrolyte. The crystal
structure of the LSPSC has a similar symmetry as LGPS, 1 dimensional ion
diffusion channels, but further improves on the Li-ion conductivity at room
temperature. The main reason of the improvement is chlorine ions that enlarge diffusion
channels; however, excess amount of Cl doping degrades the transport of Li ion
due to attractive interaction of Cl with Li. The key is to find an optimum
halide doping concentration that can maximize the Li-ion conductivity. Calculated
density of states (DOS) for LSPSC shows electrochemical instability with
approximately 3eV band gap, an insufficient value for the electrolyte material.
However, the halides near anode react with Li metal and form LiCl thin layer which
demonstrates high bandgap (about 8eV). The computational design concept for a
sulfide solid electrolyte with halide doping is a promising for high-voltage solid
state batteries.
![](https://www.aiche.org/sites/default/files/aiche-proceedings/conferences/269951/papers/571098/Paper_571098_abstract_148459_0.png)
Figure. The model systems of (a) pristine LGPS, (b) LSPS and (c) LSPSC,
the partial substitutional doping of Cl to S for LSPS. All model systems have
the BCC structure with 1 dimensional diffusion path for Li ions.