Lithium transport in Li4.4M0.4M’0.6S4 (M= Al3+, Ga3+ and M’= Ge4+, Sn4+): Combined crystallographic, conductivity, solid state NMR and computational studies

Leube, Bernhard, Inglis, Kenneth, Carrington, Elliot, Sharp, Paul, Shin, Felix, Neale, Alex, Manning, Troy, Pitcher, Michael, Hardwick, Laurence, Dyer, Matthew, Blanc, Frederic, Claridge, John and Rosseinsky, Matthew (2018) Lithium transport in Li4.4M0.4M’0.6S4 (M= Al3+, Ga3+ and M’= Ge4+, Sn4+): Combined crystallographic, conductivity, solid state NMR and computational studies. [Data Collection]

Data Catalogue DOI: 10.17638/datacat.liverpool.ac.uk/522

Description

In order to understand the structural and compositional factors controlling lithium transport in sulfides, we explored the Li5AlS4 – Li4GeS4 phase field for new materials. Both parent compounds are defined structurally by a hexagonal close packed sulfide lattice, where distinct arrangements of tetrahedral metal sites give Li5AlS4 a layered structure and Li4GeS4 a three dimensional structure related to γ-Li3PO4. The combination of the two distinct structural motifs is expected to lead to new structural chemistry. We identified the new crystalline phase Li4.4Al0.4Ge0.6S4, and investigated the structure and Li+ ion dynamics of the family of structurally related materials Li4.4M0.4M’0.6S4 (M= Al3+, Ga3+ and M’= Ge4+, Sn4+). We used neutron diffraction to solve the full structures of the Al-homologues, which adopt a layered close-packed structure with a new arrangement of tetrahedral (M/M’) sites and a novel combination of ordered and disordered lithium vacancies. AC impedance spectroscopy revealed lithium conductivities in the range 3(2) x 10-6 to 4.3(3) x 10-5 S cm-1 at room temperature with activation energies between 0.43(1) and 0.38(1) eV. Electrochemical performance was tested in a plating and stripping experiment against Li metal electrodes and showed good stability of the Li4.4Al0.4Ge0.6S4 phase over 200 hours. A combination of variable temperature 7Li solid state nuclear magnetic resonance spectroscopy and ab initio molecular dynamics calculations on selected phases showed that two dimensional diffusion with a low energy barrier of 0.17 eV is responsible for long-range lithium transport, with diffusion pathways mediated by the disordered vacancies while the ordered vacancies do not contribute to the conductivity. This new structural family of sulfide Li+ ion conductors offers insight into the role of disordered vacancies on Li+ ion conductivity mechanisms in hexagonally close packed sulfides that can inform future materials design.

Keywords:

lithium conductivity, Li sulphides, solid state NMR, X-ray diffraction

Divisions:

Faculty of Science and Engineering > School of Physical Sciences

Depositing User:

Troy Manning

Date Deposited:

30 Aug 2018 15:27

Last Modified:

30 Aug 2018 15:27

DOI:

10.17638/datacat.liverpool.ac.uk/522

URI:

https://datacat.liverpool.ac.uk/id/eprint/522

Additional details

Creators:	Leube, Bernhard Inglis, Kenneth Carrington, Elliot Sharp, Paul Shin, Felix Neale, Alex Manning, Troy Pitcher, Michael Hardwick, Laurence Dyer, Matthew Blanc, Frederic Claridge, John Rosseinsky, Matthew
Research funder:	Grant Number Name of the Funder The Funder's ID EP/N004884/1 Engineering and Physical Science Research Council 172 TS/R002517/1 INNOVATE UK (UK) 172 FIRG007 Engineering and Physical Science Research Council 172
Date:	28 August 2018
Resource language:	English
Project Details:	Project ID The title of the Project Project Funding ID Project Start Date Project End Date 115499 Integration of Computation and Experiment for Accelerated Materials Discovery 115501 1 September 2015 31 August 2020 145702 Practical and RObust Lithium Air Batteries (PROLAB) 145704 1 October 2017 30 September 2019 151119 SOLBAT - The Solid-State (Li or Na) Metal-Anode Battery 155504 1 March 2018 28 February 2021
Publisher:	University of Liverpool
Contact email address:	m.j.rosseinsky@liverpool.ac.uk
Last Modified:	30 Aug 2018 15:27