What is "eestor"

EEStor is a company based in Cedar Park, Texas, United States that claims to have developed a capacitor for electricity storage, which EEStor calls the 'Electrical Energy Storage Unit' (EESU). Key to the increased energy density of the device is not improved charge density, but dramatically higher operating voltages. The company claimed that the EESU stored more energy than lithium-ion batteries at a lower cost than lead-acid batteries used in gasoline powered cars. Such a device would revolutionize the electric car industry. Experts always said such claims were far from being realistic, and eventually, in late 2014, these claims have been shown to be over 100 times more than what the technology is actually capable of.