Amperometric oxygen sensors have come a long way since their introduction by Leland Clark in 1956 [1]. They have enjoyed a great deal of success by finding use in several applications ranging from medicine to agriculture and marine systems. In late 1990s, a lot of research efforts were focused toward the development of ultramicroelectrodes (UME) based blood gas sensors [2,3]. The mass-transfer limited steady-state current in these microdisc electrodes was shown to be proportional to the concentrations of the dissolved oxygen. Thereby, these sensors provide a convenient way to measure the amount of dissolved gases in the system of interest with high selectivity and sensitivity. Since the UME sensors work by facilitating the inner-sphere heterogeneous oxygen reduction reaction (ORR), their performance varies significantly depending on electrode material and the nature of solution. The efficiency of these sensors in common aqueous and non-aqueous media is well documented in literature, however, their performance in widely used non-aqueous battery electrolytes remains undemonstrated. Growing literature suggesting oxygen related degradation mechanisms and subsequent capacity decay in Li-ion batteries and Li-air batteries calls for the development of versatile sensors that can elucidate these processes and the correlative parasitic reactions. Therefore, it is critical to fill this knowledge gap and to evaluate the performance of UME based oxygen sensors to extend their applicability for development of mitigation strategies for oxygen related degradation in the next-generation energy storage systems.Here, we present a systematic study to evaluate the performance of different UME based oxygen sensors in the model electrolyte system of LiPF6 and TBAPF6 in ethylene carbonate:diethyl carbonate (1:1) respectively. Several sensors ranging from the traditional gold and platinum UMEs to the more recent polymer modified UMEs (Poly(3,4-ethylenedioxythiophene) or PEDOT) are investigated for the oxygen reduction reaction. Additionally, the effect of Li-ions on ORR response at these probes is studied. The results suggest that ORR in the presence of Li-ions leads to the formation of an insoluble product which fouls the UME active surface. Li-ion concentration, as low as 5mM, prevents the attainment of mass-transfer limited steady-state current and distorts the typical sigmoidal response expected from UMEs. The PEDOT UME turns out to be a promising candidate as it provides excellent selectivity towards ORR and is non-responsive towards other redox processes in the potential window of interest. Additionally, we also demonstrate the methodology for extracting useful parameters such as diffusion coefficient of oxygen in the given media using these probes. This work creates a foundation for combining the UME based probes with other advanced analytical techniques such as Scanning Electrochemical Microscopy for the real time investigation of processes such as gas evolution from electrodes and also for elucidating oxygen related degradation mechanisms in different energy storage systems.