On the nanoscale structural evolution of solid discharge products in lithium-sulfur batteries using operando scattering.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 36280671.
- Also identified by DOI 10.1038/s41467-022-33931-4 and PMC identifier 9592616.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The inadequate understanding of the mechanisms that reversibly convert molecular sulfur (S) into lithium sulfide (Li<sub>2</sub>S) via soluble polysulfides (PSs) formation impedes the development of high-performance lithium-sulfur (Li-S) batteries with non-aqueous electrolyte solutions. Here, we use operando small and wide angle X-ray scattering and operando small angle neutron scattering (SANS) measurements to track the nucleation, growth and dissolution of solid deposits from atomic to sub-micron scales during real-time Li-S cell operation. In particular, stochastic modelling based on the SANS data allows quantifying the nanoscale phase evolution during battery cycling. We show that next to nano-crystalline Li<sub>2</sub>S the deposit comprises solid short-chain PSs particles. The analysis of the experimental data suggests that initially, Li<sub>2</sub>S<sub>2</sub> precipitates from the solution and then is partially converted via solid-state electroreduction to Li<sub>2</sub>S. We further demonstrate that mass transport, rather than electron transport through a thin passivating film, limits the discharge capacity and rate performance in Li-S cells.