Chen Jiawei, Ma Kang, Song Xin, Wang Jian, Zhang Jianmin
College of Mechanical and Electrical Engineering, National Engineering Research Center for Intelligent Electrical Vehicle Power System (Qingdao), Qingdao University, Qingdao 266071, China.
College of Mechanical and Electrical Engineering, National Engineering Research Center for Intelligent Electrical Vehicle Power System (Qingdao), Qingdao University, Qingdao 266071, China; School of Materials Science and Engineering, Qingdao University, Qingdao 266071, China.
Int J Biol Macromol. 2025 Feb;288:138738. doi: 10.1016/j.ijbiomac.2024.138738. Epub 2024 Dec 17.
Polyimide membranes have long been of great interest in the battery industries due to their outstanding thermal stability and flame retardancy. However, the preparation of polyimide membranes with ideal pore structure and excellent lithium-ion transference remains a challenge. In this study, we reported for the first time, that a nano-porous fluorinated and partially carboxylated polyimide/cellulose composite membrane was successfully synthesized by selected monomers and prepared by thermal imidization, phase separation, and alkaline hydrolysis method. Particularly, an appropriate addition of cellulose acetate (CA) during the synthesis process can optimize the pore structure of the membrane. Besides, CA was converted to cellulose after alkaline hydrolysis, further enhancing the electrolyte affinity and lithium-ion transference of the membrane. Hence, this composite membrane exhibited distinct heat-resistance, high porosity (78 %), electrolyte absorption (344 %), and lithium-ion transfer number (0.84). Most importantly, thanks to the above characteristics of the membrane, the assembled LiFePO/Li cells demonstrated excellent cycling stability compared with the cell with PP membrane, showing a capacity retention rate of as high as 93 % after 500 cycles at 1C. We anticipate that this composite membrane with superior physical and electrochemical properties would shed light on the development of next-generation membranes for high-power and high-safety batteries.
聚酰亚胺膜因其出色的热稳定性和阻燃性，长期以来在电池行业备受关注。然而，制备具有理想孔结构和优异锂离子传输性能的聚酰亚胺膜仍然是一项挑战。在本研究中，我们首次报道通过选择单体，采用热亚胺化、相分离和碱水解方法，成功合成了一种纳米多孔氟化且部分羧基化的聚酰亚胺/纤维素复合膜。特别地，在合成过程中适当添加醋酸纤维素（CA）可以优化膜的孔结构。此外，CA在碱水解后转化为纤维素，进一步提高了膜对电解质的亲和力和锂离子传输性能。因此，这种复合膜表现出显著的耐热性、高孔隙率（78%）、电解质吸收率（344%）和锂离子迁移数（0.84）。最重要的是，由于该膜具有上述特性，与使用聚丙烯膜的电池相比，组装的LiFePO/Li电池表现出优异的循环稳定性，在1C倍率下500次循环后容量保持率高达93%。我们预计这种具有优异物理和电化学性能的复合膜将为下一代高功率、高安全性电池用膜的开发提供启示。
