Poly(amidoamine) dendrimer-induced 3D crosslinked network constructed on polyphenylene sulfide nonwoven as a battery separator: Effect of generation number on cell performance

Abstract

High power lithium-ion batteries put forward challenges for separator in terms of meeting high current density, safety as well as superior cycling stability. In this study, Poly(amidoamine) (PAMAM) dendrimer-introduced three-dimensional (3D) crosslinked coating layer is built on polyphenylene sulfide (PPS) nonwoven substrate to address above issues and the generation number effect are discussed thoroughly. Due to unique advantages of PAMAM dendrimer including its hydrophilicity to electrolyte, embedding effect of internal cavities, and spherical steric structure, the porosity, ionic conductivity, interfacial compatible as well as lithium-ion transference number are improved for the crosslinked composite separator especially at higher generation number, which endow battery with superior discharge capacity of 162.5 mAh g−1 at 0.2 C and outstanding C-rate capabilities. Moreover, through the adjustment of generation number, less crosslinking junctions but more crosslinking points at one junction can be achieved in PAMAM-induced 3D crosslinked structures, thus leading to the improvement of all mechanical properties concurrently. This behavior can shift the oxidative decomposition potential to 5.36 V and give superior cell performance retention (98.6%) even after 100 cycles for battery using the fourth generation PAMAM. Therefore, this study will provide a new route for separator when pursuing higher rate performance and cyclic stability.