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Joshi, Sagar Avadhutrao ; Pazhaniswamy, Sivaraj ; Plank, Christian ; Danzer, Michael A. ; Hou, Haoqing ; Cheong, Jun Young ; Breu, Josef ; Agarwal, Seema

Macromolecular Materials and Engineering, 2024. https://doi.org/10.1002/mame.202300389

Li-Hectorite (Li-Hec) clays have inherent 2D diffusion slits offering high lithium (Li+) ion conductivity. Such Li-Hec clays spontaneously delaminate into flexible nanosheets, allowing them to be coated on high-temperature stable polybenzimidazole (PBI) nanofibers laid randomly onto each other in the form of non-woven membranes. Here such Li-Hec coated PBI nonwovens are shown to be excellent Li-ion battery separators. An effective strategy based on electrospinning PBI followed by a filtration-through coating of delaminated Li-Hec nanosheets of appropriate diameter is applied to prepare the separators without the use of any binder. The composite separator shows excellent properties, such as superior wettability (solvent uptake 413%), thermostability (>500 °C), superior flame resistance, and interfacial compatibility. Additionally, the presented separator shows excellent ion conductivity, Li-ion transference number, cycling stability, and a rate performance that outperforms the common commercial separators. In summary, this work allows for a better balance between safety, high performance, and separator functionality.