Zeng Li, Cai Yingxiang, Xiang Zhihao, Zhang Yu, Xu Xuechun
Department of Physics, Nanchang University Jiangxi Nanchang 330031 P. R. China.
RSC Adv. 2018 Dec 21;9(1):92-98. doi: 10.1039/c8ra07074a. eCollection 2018 Dec 19.
Lithium-sulfur (Li-S) batteries are considered as the most promising next generation high density energy storage devices. However, the commercialization of Li-S batteries is hindered by the shuttle effect of polysulfides, the low electronic conductivity of the sulfur cathode and a large volume expansion during lithiation. Herein, we predict a new two dimensional sp hybridized carbon allotrope (PHE-graphene) and prove its thermodynamic and kinetic stability. If it is utilized to encapsulate the cathode of Li-S batteries, not only will the shuttle effect be avoided but also the electronic conductivity of the sulfur cathode will be improved significantly owing to its metallic electronic band structure. The thermal conductivity of PHE-graphene was found to be very high and even comparable with graphene, which is helpful for the heat dissipation of cathodes. In addition, PHE-graphene also exhibited superior mechanical properties including ideal tensile strength and in-plane stiffness.
锂硫（Li-S）电池被认为是最有前途的下一代高密度储能装置。然而，多硫化物的穿梭效应、硫阴极的低电子导电性以及锂化过程中的大量体积膨胀阻碍了Li-S电池的商业化。在此，我们预测了一种新的二维sp杂化碳同素异形体（PHE-石墨烯）并证明了其热力学和动力学稳定性。如果将其用于封装Li-S电池的阴极，不仅可以避免穿梭效应，而且由于其金属电子能带结构，硫阴极的电子导电性将得到显著提高。发现PHE-石墨烯的热导率非常高，甚至与石墨烯相当，这有助于阴极的散热。此外，PHE-石墨烯还表现出优异的机械性能，包括理想的拉伸强度和面内刚度。
