Novel composite gel polymer electrolytes exhibiting high ionic conductivity and good mechanical stability are prepared, and their electrochemical properties are characterized. As lithium ion sources of a single ion conductor, the core-shell structured SiO2(Li+) nanoparticles with uniform spherical shape are synthesized and used as functional fillers in the composite gel polymer electrolytes. By using the composite gel polymer electrolytes, the lithium powder polymer batteries composed of a lithium powder anode and a layered lithium vanadate (LiV3O8) cathode are assembled and their cycling performance is evaluated. The resulting lithium powder polymer batteries deliver a high discharge capacity of 264 mAh g−1 at room temperature and exhibit good capacity retention even at high current rates. The morphological analysis of the lithium powder anode reveals that the dendrite growth during cycling can be effectively suppressed by using the composite gel polymer electrolytes.