Enhancement of thermal stability and cycling performance in lithium-ion cells through the use of ceramic-coated separators

Ceramic-coated separators are prepared by coating the sides of a porous polyethylene membrane with nano-sized Al2O3 powder and hydrophilic poly(lithium 4-styrenesulfonate) binder. These separators exhibit an improved thermal stability at high temperatures without significant thermal shrinkage. Due to the high hydrophilicity of the polymer binder and large surface area of the small ceramic particles, the separators show good wettability in non-aqueous liquid electrolytes. By using the ceramic-coated separators, lithium-ion cells composed of a carbon anode and a LiCoO2 cathode are assembled and their cycling performance is evaluated. The cells are proven to have better capacity retention than for cells prepared with polyethylene membrane. It is expected that the ceramic-coated separator in this study can be potential candidate as a separator for rechargeable lithium-ion batteries that require thermal safety and good capacity retention. (C) 2009 Elsevier B.V. All rights reserved.