Oxidation potentials of electrolyte molecules in Li–sulfur (Li/S) batteries and their variations in various solvent environments are investigated using first-principles calculations in order to understand oxidative decomposition reactions of electrolytes for cathode passivation. Electrolyte solvents, Li salts, and various additives in Li/S batteries along with some Li-ion battery additives are studied. Oxidation potentials of isolated electrolyte molecules are found to be out of the operating range of typical Li/S batteries. The complexation of electrolyte molecules with Li⁺, salt anion, salt, S₈, and pyrene alters oxidation potentials compared to those of the isolated systems. The salt anion lowers oxidation potentials of electrolyte molecules by at least 4.7% while the complexes with Li⁺ have higher oxidation potentials than the isolated molecules by at least 10.4%. S₈ and pyrene, used as model compounds for sulfur and sulfur/carbon composite cathode materials, also affect oxidation potentials of electrolyte molecules, but their influence is negligible and the oxidation trends differ from those of the Li⁺ and salt anion. Although complexations change the oxidation potentials of electrolyte molecules, they are still higher than the operating voltage range of Li/S batteries, which indicates that oxidation of the studied electrolytes in Li/S batteries is not expected under ambient conditions.

中文翻译：

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锂硫电池中电解质氧化电位的第一性原理及其随环境变化而变化的†

使用第一性原理计算研究了锂硫（Li / S）电池中电解质分子的氧化电势及其在各种溶剂环境中的变化，以了解用于阴极钝化的电解质的氧化分解反应。研究了Li / S电池中的电解质溶剂，锂盐和各种添加剂，以及一些锂离子电池添加剂。发现隔离的电解质分子的氧化电势超出了典型Li / S电池的工作范围。电解质分子与Li ⁺，盐阴离子，盐，S ₈的络合与孤立的系统相比，pyr可改变氧化电位。盐阴离子使电解质分子的氧化电势降低至少4.7％，而具有Li ⁺的配合物比分离的分子具有更高的氧化电势至少10.4％。S ₈和pyr用作硫和硫/碳复合阴极材料的模型化合物，也会影响电解质分子的氧化电位，但它们的影响可以忽略不计，并且氧化趋势与Li ^{+的不同。}和盐阴离子。尽管络合物改变了电解质分子的氧化电势，但它们仍高于Li / S电池的工作电压范围，这表明在环境条件下不会期望Li / S电池中所研究的电解质发生氧化。