Cai Yingxiang, Guo Yuqing, Jiang Bo, Lv Yanan
Department of Physics, School of Science, Nanchang University, Nanchang, 330031, China.
Sci Rep. 2017 Nov 2;7(1):14948. doi: 10.1038/s41598-017-15010-7.
Sulfur cathodes in lithium-sulfur (Li-S) batteries still suffer from their low electronic conductivity, undesired dissolution of lithium polysulfide (LiS , 3 ≤ n ≤ 8) species into the electrolyte, and large degree volume change during the cycle. To overcome these problems, an effective encapsulation for the sulfur cathode is necessary. By means of particle swarm optimization (PSO) and density functional theory (DFT), we have predicted a stable metallic two-dimensional sp -hybridized carbon allotrope (DHP-graphene). This carbon sheet can prevent S atoms from cathode entering electrolyte. However, Li-ions can shuttle freely due to the increasing difference in Li-ions concentration between electrolyte and cathode along with the potential difference between cathode and anode during charge-discharge cycles. In addition, versatile electronic band structures and linear dispersion are found in DHP-graphene nanoribbons but only metallic band structure occurs for DHP-graphene nanotubes.
锂硫（Li-S）电池中的硫阴极仍然存在电子导电性低、多硫化锂（LiS ，3≤n≤8）物种 undesired 溶解到电解质中以及循环过程中体积变化大等问题。为了克服这些问题，对硫阴极进行有效的封装是必要的。通过粒子群优化（PSO）和密度泛函理论（DFT），我们预测了一种稳定的金属二维 sp 杂化碳同素异形体（DHP-石墨烯）。这种碳片可以防止阴极中的 S 原子进入电解质。然而，由于在充放电循环期间电解质和阴极之间锂离子浓度的差异增加以及阴极和阳极之间的电位差，锂离子可以自由穿梭。此外，在 DHP-石墨烯纳米带中发现了通用的电子能带结构和线性色散，但 DHP-石墨烯纳米管仅出现金属能带结构。 （注：“undesired”这里直接保留英文未翻译，因为不太明确其准确的合适中文表述，按要求不能添加解释说明）
