This patent details a method for uniformly combining two materials (material of manganese dioxide and amorphous carbon) and "growing" the composite material onto a substrate using a chemical vapor deposition process. This process results in an ultra-thin (nanometer-scale), uniform layer of the composite material, with a highly textured surface and increased conductivity. The uniform, ultra-thin layer increases consistency while reducing material cost in the manufacturing process. The highly textured surface of the electrode creates a greater electrode surface area, dramatically increasing energy storage capability of the ultra capacitor. The increased conductivity of the composite material allows for better transmission of the stored energy.
Ultra capacitors are ideal for high power applications, hybrid power systems for electrical vehicles, telecommunication devices, memory backup, standby power systems, onboard power supply, and energy storage at extreme conditions (e.g., in deep mines and military applications). The most important feature is that they have excellent reversibility and a much longer lifecycle (~ 20 years) than batteries.
The high volumetric capacitance density of ultra capacitors (10 to 100 times greater than conventional capacitors) derives from using porous electrodes to create a large, effective "plate area," and from storing energy in the diffuse double layer. This double layer, created naturally at an electrode-electrolyte interface when voltage is applied, has a thickness of only about 1 nm, thus forming an extremely small effective "plate separation," and thus high capacitance.