The development of polymer separators for Na+-ion batteries has not been of interest because conventional polyolefin (e.g., polyethylene or polypropylene) separators are not suitable for the solvation of Na+-ion-containing electrolytes. Here, we report a simple surface modification method based on chemical vapor deposition of SiO2 applied to a polyethylene separator for Na+-ion batteries. A thin SiO2 layer is coated uniformly onto a porous polymer separator with the negligibly increased total separator thickness. Improved wetting ability of the SiO2-film-coated polyethylene separators with a polar electrolyte based on ethylene carbonate (EC) and dimethyl carbonate (DMC) solvents is demonstrated, with superior electrochemical performance characteristics, such as initial specific capacity, C-rate and cyclic stability. In addition, the thin SiO2 coating film results in substantially suppressed thermal shrinkage, which may lead to improvements in the thermal and dimensional stability of Na+-ion batteries. Compared to a glass-fiber separator and the conventional PE separator, the metal-oxide-thin-film-coated polyethylene separator will accelerate the development of Na+-ion batteries for various electrochemical energy storage applications.
Bibliographical noteFunding Information:
This work was supported by the Energy Efficiency & Resources Core Technology Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP), granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea (20152010103470). This work was supported by the NRF of Korea Grant funded by the Ministry of Science, ICT, and Future Planning (NRF-2015M2A2A6A01045277, 2014M3A7B4052200).
© 2017 The Electrochemical Society.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films
- Materials Chemistry