Surface-mediated lithium ion-exchanging energy storage device

Abstract

A surface-mediated, lithium ion-exchanging energy storage device comprising: (a) A positive electrode (cathode) comprising a cathode active material that is not a functional material (bearing no functional group reactive with lithium), but having a surface area to capture or store lithium thereon; (b) A negative electrode (anode) comprising an anode active material having a surface area to capture or store lithium thereon; (c) A porous separator disposed between the two electrodes; and (d) A lithium-containing electrolyte in physical contact with the two electrodes, wherein the anode active material and/or the cathode active material has a specific surface area of no less than 100 m/g in direct physical contact with the electrolyte to receive lithium ions therefrom or to provide lithium ions thereto; wherein at least one of the two electrodes contains therein a lithium source prior to a first charge or a first discharge cycle of the energy storage device. This new generation of energy storage device exhibits the best properties of both the lithium ion battery and the supercapacitor.