The state-of-art Li-ion batteries have revolutionized the portable electronic industry and first-generation electric vehicles due to their high energy density at ambient temperatures. Owing to catastrophic failures under heat, these power devices are incompatible for applications such as in defence arsenals, subsurface drilling, space exploration and medical appliances, where performance at high-temperatures are as critical. Herein, we report an electrolyte formulation consists of Lithium bis(oxalato)borate (LiBOB) salt dissolved in propylene carbonate that enables lithium batteries to operate at extended temperature regime (>100 °C). The fundamental characterization of electrolyte system such as ionic conductivity, and internal resistance with respect to temperature promising for desired applications. Further, the electrolyte system is used to fabricate lithium batteries and the observed electrochemical results and lithium dendrites suppression capability confirmed its suitability for extended temperature applications without compromising ambient temperature performance.