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Synthetic optimization and application of Li-argyrodite Li6PS5I in solid-state battery at different temperatures

Release time:2022-02-08Hits:

Indexed by: Journal paper

Journal: RARE METALS

Included Journals: SCI

Affiliation of Author(s): School of Electrical and Electronic Engineering, Huazhong University of Science and Technology

Discipline: Engineering

First-Level Discipline: Material Science and Engineering

Document Type: J

Volume: 41

Issue: 3

Page Number: 798-805

DOI number: 10.1007/s12598-021-01827-9

Date of Publication: 2021-09-23

Impact Factor: 4.003

Abstract: Lithium argyrodite electrolytes (Li6PS5X (X=Cl, Br, I)) have received tremendous attention due to their low cost and high conductivity among sulfide electrolytes. However, the synthesis details and application of Li6PS5I in solid-state batteries have not been fully investigated yet. Here, we unravel the synthetic process for the Li6PS5I phase with the mechanical milling route, in which the argyrodite phase appears after 500 r·min-1 for 12 h. The pure Li6PS5I phase with the highest ionic conductivity (2.1  10-4 S·cm-1) is obtained after 20-h milling, and a subsequent annealing process causes a decrease of the conductivity. The Li6PS5I is applied with both the pristine and LiNbO3-coated LiNi0.7Mn0.2Co0.1O2 cathodes in solid-state batteries. The coated LiNi0.7Mn0.2Co0.1O2 material delivers higher discharge capacities (211.4 vs. 140.7 mAh·g-1 at0.05 C for the 1st cycle, and 144.0 vs. 66.5 mAh·g-1 at 0.5C for the 2nd cycle) and higher coulombic efficiencies. Moreover, the coated LiNi0.7Mn0.2Co0.1O2 electrode exhibits potential operation at -20 oC. In-situ/ex-situ EIS are applied to unravel the resistance evaluation of SSBs at different temperatures, which show that the low electrolyte conductivity and the slow lithium-ion mobility across the interface are the major bottlenecks for good electrochemical performance.