Project description
Research could lead to improved lithium–sulfur battery designs
Lithium–sulfur batteries seem to be ideal successors to conventional lithium–ion ones as they could be cheaper and hold more energy per weight. However, the energy densities achieved so far have failed to match theoretical predictions. The difficulty in loading sufficient amounts of sulfur on the porous carbon cathode limits the ability to fully develop its electrochemical potential. The EU-funded NanoEvolution project will bring attention to aspects that are not well understood. It will investigate the mass and charge transport properties of lithium–sulfur batteries and reveal more about the electrochemical reaction mechanisms, in particular multiple-step sulfur reduction. Modelling and experimental work will increase our understanding of the kinetics and morphology of lithium–sulfur deposition in carbon electrodes at unprecedented length scales.
Objective
Lithium-sulfur (Li-S) batteries are considered a strategic candidate to achieve both significantly higher energy storage and better sustainability than current Lithium-ion batteries. They operate by converting sulfur into lithium sulfide and back on discharge/charge. However, practically achieved energies are far from theoretical values due to difficulties to load sulfur in high areal and volume density in the porous carbon cathode and to fully use it electrochemically. Current experimental techniques are strong in aspects, but fail to combine the required coverage of length scales ranging from sub-nanometers to micrometers in the crucial real-time in situ fashion.
NanoEvolution aims to i) identify nanoscale structure-transport-performance correlations, ii) understand capacity limitations and reaction mechanisms, and iii) derive design criteria for improved Li-S battery performance. To achieve these goals, structure-sensitive in situ scattering and imaging methods during electrochemically operating custom-built in situ Li-S cells will be implemented. Specifically, in situ small and wide angle X-ray scattering (SWAXS) will be established and synergistically combined with nanoscale phase evolution modelling for data analysis. In situ nanoscale X-ray tomography will be realized to achieve continuous structural sensitivity from (sub-)nanometer (SWAXS) to sub-micrometer scales (tomography).
The novel combination of modelling and structure-sensitive in situ experiments allows real-time detection of the Li2S/sulfur morphology and location within the nanoporous carbon electrode during charge and discharge, at length scales so far not accessible to other methods. This allows to determine the final cause for capacity limitation (mass transport vs. charge transport), ii) elucidate the nature of the multiple-step sulfur reduction (oxidation) reaction, and iii) derive design criteria for improved sulfur loading, capacity utilization, and power densities.
Fields of science
Programme(s)
Funding Scheme
MSCA-IF - Marie Skłodowska-Curie Individual Fellowships (IF)Coordinator
8092 Zuerich
Switzerland