Strategies to Explore and Develop Reversible Redox Reactions of Li-S in Electrode Architectures Using Silver-Polyoxometalate Clusters.

Investigations of the Ag (I)-substituted Keggin K[HAgPWO] as a bifunctional Lewis acidic and basic catalyst are reported that explore the stabilization of LiS moieties so that reversible redox reactions in S-based electrodes would be possible. Spectroscopic investigations showed that the LiS-moieties can be strongly adsorbed on the {AgPWO} cluster, where the Ag(I) ion can act as a Lewis acid site to further enhance the adsorption of the S-moieties, and these interactions were investigated and rationalized using DFT. These results were used to construct an electrode for use in a Li-S battery with a very high S utilization of 94%, and a coulometric capacity of 1580 mAh g.

CoN Nanosheet Assembled Mesoporous Sphere as a Matrix for Ultrahigh Sulfur Content Lithium-Sulfur Batteries.

High utilization and loading of sulfur in cathodes holds the key in the realization of Li-S batteries. We here synthesized a CoN mesoporous sphere, which was made up of nanosheets, via an easy and convenient method. This material presents high affinity, speedy trapping, and absorbing capacity for polysulfides and acts as a bifunctional catalysis for sulfur redox processes; therefore it is an ideal matrix for S active material.