Particle Atomic Layer Deposition as an Effective Way to Enhance Li-S Battery Energy Density

Abstract Lithium-sulfur (Li-S) batteries are the most promising candidates for succeeding lithium ion batteries. However, they present some challenges which should be faced to increase its commercial possibilities as detrimental mechanisms during operation (e.g. shuttle effect, low capacity retention, anode corrosion, etc.) and sulfur cathode processing limitations (e.g. poor mechanical stability of S cathodes, defects, low S loading, etc.). Atomic layer deposition (ALD) with alumina (Al2O3) has been extensively applied to sulfur cathode surfaces to improve the electrochemical behavior of Li-S technology as it minimizes discharge product dissolution and hence, it reduces detrimental mechanisms during operation. However, the improvement of sulfur cathode processing still remains unsolved even high-cost approaches have been proposed in the-state-of-the-art which unfortunately are not viable for realistic applications. In the present work, for first time atomic layer deposition (ALD) in a fluidized bed reactor (FBR) is carried out to coat sulfur-carbon (S/C) composite particles with Al2O3 prior to electrode manufacturing. The present approach provides a precise control of S/C composite agglomeration, which improves sulfur cathode processing while maintaining the well-known satisfactory operational mechanisms related to Al2O3 coating. We reported on the economic FBR-ALD technique in an promising strategy for high specific energy density Li-S battery with an increased sulfur loading being, double of that obtained for a standard sulfur cathode (3.6 vs. 1.8 mgsulfur cm-2).