Anchoring Lithium Polysulfides via Affinitive Interactions: Electrostatic Attraction, Hydrogen Bonding, or in Parallel?

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• 作者：Zhuan Ji ; Bo Han ; Qiyang Li ; Chenggang Zhou ; Qiang Gao ; Kaisheng Xia ; Jinping Wu
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：September 3, 2015
• 年：2015
• 卷：119
• 期：35
• 页码：20495-20502
• 全文大小：480K
• ISSN：1932-7455

文摘

Stabilizing lithium polysulfides in cathodes via interactions between polysulfides and affinitive functional groups could prevent polysulfide dissolution, leading to suppressed 鈥渟huttle effect鈥?of lithium/sulfur (Li/S) batteries. Herein, four deoxynucleotides (DNs), including A (adenine-DN), T (thymine-DN), G (guanine-DN), and C (cytosine-DN), which own rich polysulfide affinitive groups, are selected to model the anchoring environments of polysulfides. Using the most soluble Li₂S₈ as probe, our first-principles simulations suggest that the interactions between polysulfides and substrates are highly correlated to the charges of affinitive sites, H-bonding environments and structural tension. The contributions from each type of interactions are quasi-quantitatively assessed. The electrostatic attractions between Li⁺ and the strong electron lone-pairs dominate the adsorption energetics, while the H-bonds formed between S₈^{2鈥?/sup> and substrate give rise to excessive stabilization. In contrast, structural distortion or rearrangement of the substrates is detrimental to the anchoring strengths. The quasi-quantitative resolution on the different interaction modes provides a facile and rational scheme for screening more efficient polysufide affinitive additives to sustain the cathode cyclicity of Li/S batteries.}