Flexible energy storage devices perform well under normal condition and their performance merits are well understood. However, energy storage under extreme conditions is still a big challenge because of electrolyte degradation and separator instability for the application such as an electrical vehicle, oil, solar energy storage, aerospace and military. Wet gels such as hydro- and organogels are mechanically strong yet brittle. Among functional gels, gel electrolytes are considered to resolve critical challenges of liquid and solid electrolytes, but they also have the property trade-offs between ion transporting and mechanical properties, as well as between strength and toughness. The performance degradation and safety issue of electrolytes prohibit flexible energy storage from operating under mechanically, thermally and electrochemically extreme conditions. Here, we report a new class of solid electrolyte, “Double Crosslinked Ionogel” based on double network concept. The tailor made ionogel electrolyte/separator structure was prepared by synthesizing double network gel from complimentary polymers and by combining it with room temperature ionic liquid. The unique structure of double crosslinked ionogel electrolyte was characterized by solid-state ¹³C CP-MAS NMR and FT-IR spectroscopies. Dual crosslinked polymer structure provide greater stretchability (strain ~250%) and high mechanical strength (3 MPa) to the electrolyte. At the same time presence of high amount of ionic liquid results (~60 wt%) in enhanced electrochemical performance i.e. Potential window (~2V), Maximum energy density (~40 Wh kg^-1) and Ionic conductivity (~1.8 mS cm^-1 at Room temp). With rGO electrodes and prepared ionogel electrolyte/separator, the supercapacitor device shows stable performance up to 180°C with good cyclic stability. High temperature promotes faster ion transport and hence results in enhanced performance in terms of rate capability (≈40%) and maximum device capacitance (≈ 32 F g^-1). There was very little performance attenuation observed even under extreme mechanical and thermal stress. The device retains around ~90 % of its initial capacitance even after 100000 of cycles at 150 °C and capable of delivering required energy and power at high temperature.