As the demand for electric vehicles and energy storage systems expands, it is essential to increase the capacity of Li-ion batteries (LIBs) applied to mid- and large-sized devices. High voltage operation of LIB and the use of high capacity electrode materials are common ways to increase the battery capacity. However, there are several problems caused by structural instability, when these electrodes are operated at high voltage. The approach of using functional additives in electrolyte is one of the effective way to improving performances. In this study, the effect of adding the functional additives in electrolyte on full cell performance at high voltage was investigated. The cycle performance of the cell operated at cut-off voltage of 4.5 V with the additives showed improvement than that of coin cell without additives. SEM image of the cycled electrodes surface with additives showed more clear morphology. It can be observed that the introduction of new functional additives effectively reduces the cell resistance by inhibiting formation of by-products during the cycling which was confirmed from the result of AC impedance and SEM images. Furthermore, the XRD patterns of the electrodes after cycling exhibited improved stability with the addition of functional additive used in this work. Our results clearly indicate the significance of additive selection for promising high voltage operation of lithium-ion batteries.