Sulfonated SiO2 particles containing poly(lithium 4-styrenesulfonte) in their shell are synthesized and used as coating materials for the preparation of ceramic-coated separators for lithium-ion cells. The ceramic-coated separators exhibit good thermal stability and wettability for liquid electrolyte due to the presence of a heat-resistant silica with hydrophilic poly(lithium 4-styrenesulfonte). By using these ceramic-coated separators, lithium-ion cells composed of a carbon negative electrode and a LiNi1/3Co1/3Mn1/3O2 positive electrode are assembled and their cycling performances are evaluated. The cells assembled with the ceramic-coated separators demonstrate superior cycling performance compared to cell prepared with a polyethylene separator.