25-30 August 2019
Henry Ford Building
Europe/Berlin timezone

Probing Ion Mobility Mechanisms in Solid Electrolytes using Solid-State NMR

26 Aug 2019, 16:15
35m
Lecture Hall A (Henry Ford Building)

Lecture Hall A

Henry Ford Building

Invited talk Materials applications Materials

Speaker

Dr Karen Johnston (Durham University)

Description

All-solid-state Li-ion batteries are attracting considerable attention as possible alternatives to conventional liquid electrolyte-based devices as they present a viable opportunity for increased energy density and safety. In recent years, a number of candidate materials have been explored as possible solid electrolytes, including garnets, Li-stuffed garnets, Li-rich anti-perovskites (LiRAPs), thio-LISICONs and complex spinels. LiRAPs, including Li3−xOHxCl, have generated considerable interest based on their reported ionic conductivities (on the order of 10−3 S cm−1).1,2 However, until very recently, their lithium and proton transport capabilities as a function of composition were not fully understood. Hence, current research efforts have focused on the synthesis and structural characterisation of Li3−xOHxCl using a combination of ab initio molecular dynamics and variable-temperature 1,2H, 7Li and 35Cl solid-state NMR spectroscopy. Using this unique combination of techniques, it is possible to study the mobility of both the Li ions and protons. We will demonstrate that Li-ion transport is highly correlated with the proton and Li-ion vacancy concentrations. In particular, we will show that the Li ions are free to move throughout the structure, whilst the protons are restricted to solely rotation of the OH groups. Based on these findings, and the strong correlation between long-range Li-ion transport and OH rotation, we have proposed a new Li-ion hopping mechanism, which suggests that the Li-rich anti-perovskite system is an excellent candidate electrolyte for all-solid-state batteries.3 However, to fully understand the mechanism for conduction, multiple, complementary characterisation techniques are needed.

References

  1. Y. Zhao and L. L. Daemen, J. Am. Chem. Soc., 2012, 134, 15042.
  2. A. Emly, E. Kioupakis and A. Van der Ven, Chem. Mater., 2013, 25, 4663.
  3. J. A. Dawson, T. S. Attari, H. Chen, S. P. Emge, K. E. Johnston and M. S. Islam, Energy Environ. Sci., 2018, 10, 2993.

Primary authors

Dr Karen Johnston (Durham University) Ms Tavleen Attari (Durham University) Mr Theodosis Famprikis (Universite de Picardie Jules Verne) Dr James Dawson (University of Bath) Prof. Christian Masquelier (Universite de Picardie Jules Verne) Prof. Saiful Islam (University of Bath)

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