Nanodiamond-Enhanced Nanofiber Separators for High-Energy Lithium-Ion Batteries
Aashray Narla, Wenbin Fu, Alp Kulaksizoglu, Atsushi Kume, Billy Johnson, Ashwin Sankara Raman, Fujia Wang, Alexandre Magasinski, Do Youb Kim, Mohammed Kousa, Yiran Xiao, Samik Jhulki, Kostiantyn Turcheniuk, Gleb Yushin
Abstract
High Resolution Image Download MS PowerPoint Slide Current lithium-ion battery separators made from polyolefins such as polypropylene and polyethylene generally suffer from low porosity, low wettability, and slow ionic conductivity and tend to perform poorly against heat-triggering reactions that may cause potentially catastrophic issues, such as fire. To overcome these limitations, here we report that a porous composite membrane consisting of poly(vinylidene fluoride- co -hexafluoropropylene) nanofibers functionalized with nanodiamonds (NDs) can realize a thermally resistant, mechanically robust, and ionically conductive separator. We critically reveal the role of NDs in the polymer matrix of the membrane to improve the thermal, mechanical, crystalline, and electrochemical properties of the composites. Taking advantages of these characteristics, the ND-functionalized nanofiber separator enables high-capacity and stable cycling of lithium cells with LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC811) as the cathode, much superior to those using conventional polyolefin separators in otherwise identical cells.