Ab initio studies of structural features not easily amenable to experiment

Reconstruction of zinc-metal battery solvation structures operating from -50 ~ +100 °C

Serious solvation effect of zinc ions has been considered as the cause of the severe side reactions (hydrogen evolution, passivation, dendrites, and etc.) of aqueous zinc metal batteries. Even though the regulation of cationic solvation structure has been widely studied, effects of the anionic solvation structures on the zinc metal were rarely examined. Herein, co-reconstruction of anionic and cationic solvation structures was realized through constructing a new multi-component electrolyte (Zn(BF4)2-glycerol-boric acid-chitosan-polyacrylamide, simplified as ZGBCP), which incorporates double crosslinking network via the esterification, protonation and polymerization reactions, thereby combining multiple advantages of 'liquid-like' high conductivity, 'gel-like' robust interface, and 'solid-like' high Zn2+ transfer number. Based on the ZGBCP electrolyte, the Zn anodes achieve record-low polarization and stable cycling. Furthermore, the ZGBCP electrolyte renders the AZMBs ultrawide working temperature (-50 °C ~ +100 °C) and ultralong cycle life (30000 cycles), which further validates the feasibility of the dual solvation structure strategy and provides a innovative perspective for the development of high-performance AZMBs.

Computational analysis of the potential energy surfaces of glycerol in the gas and aqueous phases: effects of level of theory, basis set, and solvation on strongly intramolecularly hydrogen-bonded systems

The 126 possible conformations of 1,2,3-propanetriol (glycerol) have been studied by ab initio molecular orbital and density functional theory calculations in the gas and aqueous phases at multiple levels of theory and basis sets. The partial potential energy surface for glycerol as well as an analysis of the conformational properties and hydrogen-bonding trends in both phases have been obtained. In the gas phase at the G2(MP2) and CBS-QB3 levels of theory, the important, low-energy conformers are structures 100 and 95. In the aqueous phase at the SM5.42/HF/6-31G* level of theory, the lowest energy conformers are structures 95 and 46. Boltzmann distributions have been determined from these high-level calculations, and good agreement is observed when these distributions are compared to the available experimental data. These calculations indicate that the enthalpic and entropic contributions to the Gibbs free energy are important for an accurate determination of the conformational and energetic preferences of glycerol. Different levels of theory and basis sets were used in order to understand the effects of nonbonded interactions (i.e., intramolecular hydrogen bonding). The efficiency of basis set and level of theory in dealing with the issue of intramolecular hydrogen bonding and reproducing the correct energetic and geometrical trends is discussed, especially with relevance to practical computational methods for larger polyhydroxylated compounds, such as oligosaccharides.