Due to the need for reducing system size and weight while increasing performance, many military and commercial systems today require high-temperature electronics to run actuators, high-speed motors or generators. Of the many passive devices required to satisfy the needs for a complete high temperature system, none has been more problematic than the capacitor, particularly for larger devices requiring values of several micro-or milli-farads. Here we introduce a polymer metal composite we have recently developed that meets typical aerospace design constraints of high reliability, robustness, light-weight, as well as high temperature (up to 300°C) operation.Our recent discovery of the capacitive behaviour in perfluorinated sulfonic acid polymers sandwiched between metal electrodes has lead to the exciting development of high temperature capable high density passive storage components. These composites exhibit capacitance per unit planar area of ~1.0 mF cm -2 or 40 mF/g for a ~100 µm-thick polymer substrate, with only a small predictable decrease in capacitance immediately after heating to 100°C followed by constant capacitance up to 300°C. Here we report the design and testing of single step microfabrication of metal electrodes to these polymer composites sandwiched between two thin metal films along with their performance at high temperatures.