Bai Lu, Chen Xiaoqi, Zhang Fen, Zhou Haijun, Li Yantao, Wang Peng, Li Na, Xiao Jijun
Institute of Energy Resources, Hebei Academy of Sciences, Shijiazhuang 050081, China.
Hebei Key Laboratory of Flexible Functional Materials, School of Materials Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050000, China.
ACS Omega. 2024 Jul 12;9(29):31620-31630. doi: 10.1021/acsomega.4c01669. eCollection 2024 Jul 23.
Solid polymer electrolytes have attracted considerable attention, owing to their flexibility and safety. At present, poly(ethylene oxide) is the most widely studied polymer electrolyte matrix. It exhibits higher safety than the polyolefin diaphragm used in traditional lithium-ion batteries. However, it readily crystallizes at room temperature, resulting in low ionic conductivity, and the preparation process involves organic solvents. In this study, from the perspective of molecular design, solvent-free polyaspartate polyurea (PAEPU) and the cheap and easily available polypropylene (PP) nonwoven fabric were used as support materials for the PAEPU/PP composite solid polymer electrolyte (PAEPU/PP -CPE). This CPE has good thermal stability, dimensional stability, flexibility, and mechanical properties. Among the different CPEs that were analyzed, PAEPU/PP-CPE@20 had the highest ionic conductivity, which was reinforced with 10 g/m PP nonwoven fabric and the content of lithium salt was 20 wt %. Furthermore, PAEPU/PP-CPE@20 exhibited the highest electrochemical stability with an electrochemical window value of 5.53 V. Moreover, the capacity retention rate of the Li//PAEPU/PP-CPE@20//LiFePO half-cell was 96.82% after 150 cycles at 0.05 C and 60 °C, and the capacity recovery rate in the rate test reached 98.81%.
固态聚合物电解质因其柔韧性和安全性而备受关注。目前，聚环氧乙烷是研究最为广泛的聚合物电解质基体。它比传统锂离子电池中使用的聚烯烃隔膜具有更高的安全性。然而，它在室温下容易结晶，导致离子电导率较低，并且制备过程涉及有机溶剂。在本研究中，从分子设计的角度出发，将无溶剂的聚天冬氨酸聚脲（PAEPU）和廉价易得的聚丙烯（PP）无纺布用作PAEPU/PP复合固态聚合物电解质（PAEPU/PP-CPE）的支撑材料。这种CPE具有良好的热稳定性、尺寸稳定性、柔韧性和机械性能。在分析的不同CPE中，PAEPU/PP-CPE@20的离子电导率最高，它用10 g/m的PP无纺布增强，锂盐含量为20 wt%。此外，PAEPU/PP-CPE@20表现出最高的电化学稳定性，电化学窗口值为5.53 V。而且，Li//PAEPU/PP-CPE@20//LiFePO半电池在0.05 C和60 °C下循环150次后的容量保持率为96.82%，倍率测试中的容量恢复率达到98.81%。
