Enhanced electrochemical performance of aluminum-ion batteries with novel polyimide nanofiber separators
Wenjing Fu, Yuefeng Su, Lai Chen, Hongtao Cao, Yaning Yang, Jianbiao Liu, Yuxi Wu, Zhiyu Hu, Kang Yan, Peng Li
Abstract
For the first time, polyimide (PI) nanofiber membranes were fabricated using the electrospinning technique for aluminum-ion batteries . The microstructure, thermal stability, and mechanical properties of the PI membrane were thoroughly characterized, and Fourier-transform infrared spectroscopy was employed to confirm the complete imidization during the stepwise thermal process. The PI nanofiber membranes as separators were then tested in aluminum-ion batteries, where they were combined with graphite cathodes and aluminum foil anodes. The specific capacities for the PI and glass fiber separator systems were 77.2 and 74.7mAh g⁻¹, respectively. Aluminum cells with PI separators have higher specific capacity and coulombic efficiency compared to aluminum ion cells with GF separators under constant-current long-term cycling at current densities of 25 mA g⁻¹ and 100 mA g⁻¹.Furthermore, symmetric cells employing PI separators exhibited lower voltage polarization compared to that with glass fiber separator. Scanning electron microscopy (SEM) images of aluminum anodes after 50 stripping/deposition cycles revealed that the aluminum anodes in batteries with PI separators closely resembled the original aluminum foil , indicating a more efficient aluminum stripping/deposition process and more uniform aluminum deposition. These results demonstrate the feasibility of using PI nanofiber membranes in aluminum-ion batteries and offer new insights into the development of high performance separators for aluminum-ion batteries.