Bui Van-Tien, Nguyen Van-Toan, Nguyen Ngoc-Anh, Umapathi Reddicherla, Larina Liudmila L, Kim Jong Heon, Kim Hyun-Suk, Choi Ho-Suk
Department of Chemical Engineering and Applied Chemistry, Chungnam National University, Yuseong-Gu, Daejeon 34134, Korea.
Department of Materials Science and Engineering, Chungnam National University, Yuseong-Gu, Daejeon 34134, Korea.
Membranes (Basel). 2021 Jan 7;11(1):41. doi: 10.3390/membranes11010041.
The development of highly porous and thin separator is a great challenge for lithium-ion batteries (LIBs). However, the inevitable safety issues always caused by poor mechanical integrity and internal short circuits of the thin separator must be addressed before this type of separator can be applied to lithium-ion batteries. Here, we developed a novel multilayer poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) membrane with a highly porous and lamellar structure, through a combination of evaporation-induced phase separation and selective solvent etching methods. The developed membrane is capable of a greater amount of electrolyte uptake and excellent electrolyte retention resulting from its superior electrolyte wettability and highly porous structure, thereby offering better electrochemical performance compared to that of a commercial polyolefin separator (Celgard). Moreover, benefiting from the layered configuration, the tensile strength of the membrane can reach 13.5 MPa, which is close to the mechanical strength of the Celgard type along the transversal direction. The elaborate design of the multilayered structure allows the fabrication of a new class of thin separators with significant improvements in the mechanical and electrochemical performance. Given safer operation, the developed multilayer membrane may become a preferable separator required for high-power and high-energy storage devices.
开发高度多孔且薄的隔膜对锂离子电池（LIBs）来说是一项巨大挑战。然而，在这种类型的隔膜应用于锂离子电池之前，必须解决由薄隔膜机械完整性差和内部短路引发的不可避免的安全问题。在此，我们通过蒸发诱导相分离和选择性溶剂蚀刻方法相结合，开发出一种具有高度多孔和层状结构的新型多层聚（偏二氟乙烯 - 共 - 六氟丙烯）（PVDF - HFP）膜。所开发的膜由于其优异的电解质润湿性和高度多孔结构，能够吸收大量电解质并具有出色的电解质保留能力，从而与商用聚烯烃隔膜（Celgard）相比提供了更好的电化学性能。此外，受益于层状结构，该膜的拉伸强度可达13.5 MPa，这与Celgard型隔膜沿横向方向的机械强度相近。多层结构的精心设计使得能够制造出一类新型薄隔膜，其机械和电化学性能有显著提升。考虑到操作更安全，所开发的多层膜可能成为高功率和高能量存储设备所需的优选隔膜。
