Global energy source demand is increasing, prompting a leap in energy storage system development. Recent developments in electrochemical industries opened a novel strategy to solve the current energy crisis without compromising with environmental integrity. In the global supply chain for portable devices and grid applications, secondary batteries play a crucial role in energy storage. Due to limited energy density, the present secondary energy storage devices are not able to satisfy the increasing energy demand. Researchers around the globe shifted their focus to batteries with larger power density and in repsonse to the aforementioned, various research and study into the lithium ion battery quickly rose to prominence. Unique features of nanofillers make them a promising candidate for energy storage applications. Nanofillers are generally inorganic materials which acts as additives in solid form to the nanocomposite matrix which enables the manipulation of properties of nanocomposites. Nanofillers can increase the ionic conductivity that leads to enhancement of energy density because of large number of conducting free paths with a large surface area. This chapter discusses deeply into the significance of nanofillers in improving the output features and the influence it has on energy storage devices.