A charge storage device comprising: a first electrode; a second electrode being opposed to and spaced apart from the first electrode; a porous separator disposed between the electrodes; a sealed package for containing the electrodes, the separator and an electrolyte in which the electrodes are immersed; and a first terminal and a second terminal being electrically connected to the first electrode and the second electrode respectively and both extending from the package to allow external electrical connect to the respective electrodes, wherein the gravimetric FOM of the device is greater than about 2.1 Watts/gram. Also described is a method of manufacturing a charge storage device, the method comprising the steps of: providing a first electrode; disposing a second electrode in opposition to and spaced apart from the first electrode; disposing a porous separator between the electrodes; containing within a sealed package the electrodes, the separator and an electrolyte, wherein the electrodes are immersed in the electrolyte; and electrically connecting a first terminal and a second terminal to the first electrode and the second electrode respectively such that the terminals extending from the package to allow external electrical connection to the respective electrodes, wherein the gravimetric FOM of the device is greater than about 2.1 Watts/gram.