We have designed a new class of nanocomposite polymer electrolyte with a view to understand the origin and nature of interactions occurring between the surface of filler nanoparticles into polymer chain and the migration ionic species. The high-performance soft, matter like nanocomposite polymer electrolyte has been prepared by initiating complex formation between silver triflate (AgCF3SO3) salt and a low molecular weight amorphous polymer poly(propylene glycol) (PPG) (4000) with different amounts of CeO2 nanoparticles. The ionic interactions between the filler nanoparticles and the host polymer have been investigated by FTIR studies. The surface interactions of filler nanoparticles play a pivotal role in enhancing both the carrier concentration and the segmental mobility and registering the maximum ionic conductivity of 5.2×10−4S cm−1 at room temperature. A percolating network of filler nanoparticles leads to a more flexible matrix, thus facilitating the chain mobility of polymer chain as examined by differential scanning calorimetric (DSC) studies. Detailed ion dynamics and segmental relaxation of electrolyte complex have been analyzed by the impedance data as a function of frequency at varying temperatures.