Critical challenges of Li–S batteries are related with the instability of Li metal during cycling. To overcome these issues, electrolyte modification and artificial SEI layer incorporation-based strategies have been here reviewed.

No abstract

Distinctive surface functional groups on 3D MXenes as Pt-supports are correlated with optimized Pt–H affinity and HER activity in alkaline media.

Lithium−oxygen batteries are promising next-generation high-energy storage candidates. Replacing pure O 2 with air and uncovering moisture and CO 2contamination effects on the O 2 electrochemistry, however, represent necessary steps toward commercialization. Representatively, a CO 2 -induced shift toward Li 2 CO 3 formation has been systematically disclosed in a number of electrolyte solvents. Here, we show that in tetraglyme only Li 2 CO 3 is formed without Li 2 O 2 . Using explicit theoretical calculations, we reveal that discharge is governed by the strong chelation effect induced by oxygen lone electron pairs of the glyme, which emphasizes the importance of assessing direct interatomic interactions between Li + and solvent molecules when determining preferred reaction pathways in these O 2 /CO 2 systems. The choice of the electrolyte counteranion investigated here for the first time, however, has no apparent effect on the O 2 /CO 2 electrochemistry, leading to Li 2 CO 3 . Galvanostatic results and product analysisnonetheless reveal that highly dissociated Li + counteranions in tetraglyme favorably stabilize soluble peroxocarbonate reaction intermediates during discharge, whereas highly associated salts accelerate Li 2 CO 3 precipitation, dramatically narrowing the cell capacity. Importantly, these observations are also distinct from prior conclusions from rationally designed electrolytes under pure O 2 conditions and emphasize the need to revisit established correlations between uncovered counteranion•••Li + •••solvent interaction degrees and the balance between mechanistic pathways in practical Li− air devices.

No abstract