Nanodiamond-Enhanced Nanofiber Separators for High-Energy Lithium-Ion Batteries

• Published in: ACS applied materials & interfaces 2023-07, Vol.15 (27), p.32678-32686
• Main Authors: Narla, Aashray, Fu, Wenbin, Kulaksizoglu, Alp, Kume, Atsushi, Johnson, Billy R., Raman, Ashwin Sankara, Wang, Fujia, Magasinski, Alexandre, Kim, Doyoub, Kousa, Mohammed, Xiao, Yiran, Jhulki, Samik, Turcheniuk, Kostiantyn, Yushin, Gleb
• Format: Article
• Language: English
• Subjects: Functional Nanostructured Materials (including low-D carbon)
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.3c04305

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 LiNi0.8Mn0.1Co0.1O2 (NMC811) as the cathode, much superior to those using conventional polyolefin separators in otherwise identical cells.