DGIST Scholar: Integrated study of first principles calculations and experimental measurements for Li-ionic conductivity in Al-doped solid-state LiGe2(PO4)(3) electrolyte

Department of Energy Science and Engineering Energy Systems Engineering 1. Journal Articles

Cited time in webofscience

Cited time in scopus

Integrated study of first principles calculations and experimental measurements for Li-ionic conductivity in Al-doped solid-state LiGe2(PO4)(3) electrolyte

Title: Integrated study of first principles calculations and experimental measurements for Li-ionic conductivity in Al-doped solid-state LiGe2(PO4)(3) electrolyte

Author(s): Kang, Joonhee ; Chung, Habin ; Doh, Chilhoon ; Kang, Byoungwoo ; Han, Byungchan

Issued Date: 2015-10-20

Citation: Journal of Power Sources, v.293, pp.11 - 16

Type: Article

Author Keywords: Li-ion batteries ; First principles ; Solid-state electrolyte ; Ionic conductivity ; Diffusion mechanism

Keywords: Ab Initio Molecular Dynamics ; ACTIVATION ; Activation Energy ; Aluminum ; Atoms ; Calculations ; CATHODE ; Chemical Activation ; CONDUCTORS ; Density Functional Theory ; Diffusion Mechanism ; Diffusion Mechanisms ; Electrochemical Properties ; Electrolytes ; ENERGY ; First-Principles Calculation ; First Principles ; First Principles Density Functional Theory (DFT) Calculations ; GE ; Germanium ; GLASS-CERAMICS ; Ionic Conduction in Solids ; Ionic Conductivity ; Li-Ion Batteries ; Lithium ; Lithium-Ion Batteries ; LITHIUM BATTERY ; Molecular Dynamics ; Nudged Elastic Band Methods ; PHOSPHATE ; Solid-State Electrolyte ; Solid Electrolytes ; STABILITY

ISSN: 0378-7753

Abstract: Understanding of the fundamental mechanisms causing significant enhancement of Li-ionic conductivity by Al3+ doping to a solid LiGe2(PO4)3 (LGP) electrolyte is pursued using first principles density functional theory (DFT) calculations combined with experimental measurements. Our results indicate that partial substitution Al3+ for Ge4+ in LiGe2(PO4)3 (LGP) with aliovalent (Li1+xAlxGe2-x(PO4)3, LAGP) improves the Li-ionic conductivity about four-orders of the magnitude. To unveil the atomic origin we calculate plausible diffusion paths of Li in LGP and LAGP materials using DFT calculations and a nudged elastic band method, and discover that LAGP had additional transport paths for Li with activation barriers as low as only 34% of the LGP. Notably, these new atomic channels manifest subtle electrostatic environments facilitating cooperative motions of at least two Li atoms. Ab-initio molecular dynamics predict Li-ionic conductivity for the LAGP system, which is amazingly agreed experimental measurement on in-house made samples. Consequently, we suggest that the excess amounts of Li caused by the aliovalent Al3+ doping to LGP lead to not only enhancing Li concentration but also opening new conducting paths with substantially decreases activation energies and thus high ionic conductivity of LAGP solid-state electrolyte. © 2015 Published by Elsevier B.V.