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Theoretically, lithium–sulfur (Li‐S) batteries are highly promising candidates for renewable energy applications, given their scalable energy density and low cost. However, their current practical performance is limited below theoretical expectations, despite attempts to accommodate volumetric expansion and improve electrical conductivity with porous S‐anchoring supports. Battery performance is primarily rate‐limited by the sluggish redox and conversion reaction kinetics of lithium polysulfides (LiPS), which respectively transform into lithium sulfide (Li2S) and elemental S through charging and discharging galvanostatic cycles. Given their strong electrocatalytic performance and other pertinent benefits, recent research highlights single‐atom catalysts (SACs) as candidates for enhancing Li‐S batteries. Thus, this review summarizes contemporary advancements regarding SAC implementation in Li‐S batteries, primarily emphasizing catalyst morphology, battery performance, and mechanistic elucidation. More specifically, separators and cathodes can be engineered via SACs to better anchor LiPS and improve their reductive kinetics, thereby inhibiting the "shuttle effect" known to impact Li‐S batteries. In addition, SACs can be modulated with functional groups to synergistically improve performance, enabling higher S loadings and redistributing transferred charge. Overall, SACs conspicuously boost Li‐S battery performance, justifying further research toward their implementation in Li‐S batteries. [ABSTRACT FROM AUTHOR]

The structural dynamics of Cu catalyst regeneration from Cu2O under methanol is poorly understood. In situ Environmental TEM on Cu(100)-supported Cu2O islands reveals a transition from anisotropic to isotropic shrinking during reduction. Two-stage reduction is statistically supported and explained by preferential methanol reactivity on Cu2O nano-islands with DFT simulations. [ABSTRACT FROM AUTHOR]

Oxygen vacancies in perovskite oxide solid solutions are fundamentally interesting and technologically important. However, experimental characterization of the vacancy locations and their impact on electronic structure is challenging. We have carried out first-principles calculations on two Zr-modified solid solutions, Pb(Zn1/3Nb2/3)O3 and Pb(Mg1/3Nb2/3)O3, in which vacancies are present. We find that the vacancies are more likely to reside between low-valent cation-cation pairs than high-valent cation-cation pairs. Based on the analysis of our results, we formulate guidelines that can be used to predict the location of oxygen vacancies in perovskite solid solutions. Our results show that vacancies can have a significant impact on both the conduction and valence band energies, in some cases lowering the band gap by ≈0.5 eV. The effects of vacancies on the electronic band structure can be understood within the framework of crystal field theory. [ABSTRACT FROM AUTHOR]

The development of accurate methods for determining how alloy surfaces spontaneously restructure under reactive and corrosive environments is a key, long-standing, grand challenge in materials science. Using machine learning-accelerated density functional theory and rare-event methods, in conjunction with in situ environmental transmission electron microscopy (ETEM), we examine the interplay between surface reconstructions and preferential segregation tendencies of CuNi(100) surfaces under oxidation conditions. Our modeling approach predicts that oxygen-induced Ni segregation in CuNi alloys favors Cu(100)-O c(2 × 2) reconstruction and destabilizes the Cu(100)-O (2√2 × √2) R 45° missing row reconstruction (MRR). In situ ETEM experiments validate these predictions and show Ni segregation followed by NiO nucleation and growth in regions without MRR, with secondary nucleation and growth of Cu 2 O in MRR regions. Our approach based on combining disparate computational components and in situ ETEM provides a holistic description of the oxidation mechanism in CuNi, which applies to other alloy systems.

The structural dynamics of Cu catalyst regeneration from Cu 2 O under methanol is poorly understood. In situ Environmental TEM on Cu(100)-supported Cu 2 O islands reveals a transition from anisotropic to isotropic shrinking during reduction. Two-stage reduction is statistically supported and explained by preferential methanol reactivity on Cu 2 O nano-islands with DFT simulations.