Hussain Arshad, Luo Yang, Li Tianyu, Zhang Hongzhang, Mirza Shahid, Zhang Huamin, Li Xianfeng
Division of Energy Storage, Dalian National Laboratory for Clean Energy (DNL), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, P. R. China.
University of Chinese Academy of Sciences, Beijing 100049, P. R. China.
ACS Appl Mater Interfaces. 2020 Dec 16;12(50):55809-55819. doi: 10.1021/acsami.0c15549. Epub 2020 Dec 7.
Lithium-sulfur (Li-S) batteries are considered as one of the most prospective candidates for electric vehicles, due to their superior theoretical energy density and low cost. However, the issues of polysulfide ion (PS) shuttling and uncontrollable Li dendrite growth hindered their further application. Herein, a multifunctional nanoporous polybenzimidazole (PBI) membrane with well-controllable morphology was successfully designed and fabricated to address the aforementioned obstacles. In this design, the PBI membrane could offer strong chemical binding interaction with PS, thus applying dynamic adsorption toward PS as well as stable sulfur electrochemistry, which is further verified by experiments and density functional theory (DFT) simulation. Moreover, PBI membranes with high porosity and high electrolyte uptake capability can provide ample lithium storage space and abundant Li supplements to facilitate Li deposition and improve Li metal batteries' cyclic stability. Besides that, the PBI membrane has excellent mechanical and thermal stability and exclusive flame resistance, which guarantees the safety of the Li-S battery as well. As a result, Li-S batteries assembled with an as-developed PBI membrane demonstrated a remarkable rate capability of 780 mAh g at 2C and an impressive reversible capacity of 523 mAh g at 0.5C after 400 cycles, which is much higher than the commercial separators. More importantly, even with a lofty sulfur loading of 3 mg cm, a high discharge capacity of 744 mAh g (capacity retention 93.96%, at 0.1C after 100 cycles) can also be achieved. Overall, the current study highlighted a robust material platform for stable, safe, and efficient multifunctional separators for high-performance Li-S batteries.
锂硫（Li-S）电池因其卓越的理论能量密度和低成本，被视为电动汽车最具前景的候选电池之一。然而，多硫化物离子（PS）穿梭和锂枝晶不可控生长的问题阻碍了它们的进一步应用。在此，成功设计并制备了一种形貌可控的多功能纳米多孔聚苯并咪唑（PBI）膜，以解决上述障碍。在这种设计中，PBI膜能与PS提供强烈的化学结合相互作用，从而对PS进行动态吸附以及实现稳定的硫电化学，这通过实验和密度泛函理论（DFT）模拟得到进一步验证。此外，具有高孔隙率和高电解质吸收能力的PBI膜可以提供充足的锂存储空间和丰富的锂补充，以促进锂沉积并提高锂金属电池的循环稳定性。除此之外，PBI膜具有优异的机械和热稳定性以及独特的阻燃性，这也保证了Li-S电池的安全性。结果，用所开发的PBI膜组装的Li-S电池在2C时表现出780 mAh g的显著倍率性能，在400次循环后于0.5C时具有523 mAh g的可观可逆容量，这远高于商业隔膜。更重要的是，即使硫负载量高达3 mg cm，在100次循环后于0.1C时仍可实现744 mAh g的高放电容量（容量保持率93.96%）。总体而言，当前研究突出了一个强大的材料平台，用于高性能Li-S电池稳定、安全且高效的多功能隔膜。
