Core-shell structured SiO2 particles with a poly(lithium acrylate) shell were synthesized and used in preparing a composite gel electrolyte. The composite gel electrolyte exhibited high ionic conductivity and favorable interfacial characteristics at the lithium electrode. The use of a composite gel electrolyte containing SiO2(Li+) particles effectively suppressed both the dendrite growth of lithium and-dissolution-of-transition metals from the active LiNi0.5Mn1.5O4 material. The lithium metal polymer cell composed of a lithium negative electrode and a LiNi0.5Mn1.5O4 positive electrode delivered a high discharge capacity of 136.6 mAh g(-1) and exhibited good capacity retention. (C) 2015 The Electrochemical Society. All rights reserved.