Beijing Key Laboratory of Environmental Science and Engineering, School of Materials Science and Engineering , Beijing Institute of Technology , 5# South Zhongguancun Street , Beijing 100081 , China.
Collaborative Innovation Center of Electric Vehicles in Beijing , Beijing 100081 , China.
ACS Appl Mater Interfaces. 2019 Nov 20;11(46):43252-43260. doi: 10.1021/acsami.9b16294. Epub 2019 Nov 11.
All-solid-state sodium ion batteries (ASIBs) possess enhanced safety and desired cycling life compared with conventional liquid sodium batteries, showing great potential in large-scale energy storage systems. Polymer electrolytes based on poly(ethylene oxide) (PEO) have been extensively studied for ASIBs due to superior flexibility and processability. However, PEO-based electrolyte without any modification can hardly meet the requirements of ASIBs at room temperature. In the past decade, unremitting efforts have been attached to inhibiting crystallization of PEO, especially via ionic liquid plasticizing. However, the plasticizing mechanism is not clear. Here we incorporated PyrFSI into PEO-NaClO electrolyte to investigate the plasticizing effect by infrared spectrum characterizations and DFT calculations. The results indicate that FSI anions tend to adhere to the PEO backbone, generating enhanced coordination ability and more coordination sites. Solid-state sodium ion batteries using PEO-NaClO-40 wt % PyrFSI as polymer electrolyte exhibit good cycling and rate performance. Insights into the plasticizing mechanism contribute to fabricating polymer electrolyte with high performance for ASIBs.
全固态钠离子电池 (ASIBs) 相较于传统的液态钠电池具有更高的安全性和理想的循环寿命，在大型储能系统中具有巨大的应用潜力。基于聚环氧乙烷 (PEO) 的聚合物电解质因其优异的柔韧性和加工性能而被广泛研究用于 ASIBs。然而，未经任何改性的 PEO 基电解质很难满足室温下 ASIBs 的要求。在过去的十年中，人们一直在不懈努力抑制 PEO 的结晶，特别是通过离子液体增塑。然而，其增塑机制尚不清楚。在这里，我们将 PyrFSI 掺入到 PEO-NaClO 电解质中，通过红外光谱表征和 DFT 计算来研究其增塑效果。结果表明，FSI 阴离子倾向于与 PEO 主链结合，从而产生增强的配位能力和更多的配位位点。使用 PEO-NaClO-40wt% PyrFSI 作为聚合物电解质的固态钠离子电池表现出良好的循环和倍率性能。对增塑机制的深入了解有助于制备用于 ASIBs 的高性能聚合物电解质。
