リチウムイオンキャパシタの開発・製品化動向と応用展開

Abstract

The lithium ion capacitor (LIC) is a new hybrid capacitor, in which the materials and the charge and discharge processes are different in the positive and negative electrodes. Generally, positive electrode materials are a kind of activated carbon as used for an EDLC electrode, and negative electrode materials are a kind of carbon materials as used for an LIB negative electrode. Also the negative electrode of the LIC is doped in advance with lithium ions using a pre-doping process. Because of the difficulty of the pre-doping process, early LICs had a small capacitance, but the development of a new pre-doping method is a breakthrough, and the commercialization and mass production of a large capacitance LIC has been accelerated. With the negative electrode doped with lithium ions, the LIC achieves a four times higher energy density than that of an EDLC, and also maintains the superior performance of EDLC, i.e. high power density and very long cycle life. The LIC has already started to be used in various industries such as the energy, electrical power and automobile industries. The LIC will replace not only EDLCs but also other secondary batteries such as the lead acid battery or the LIB in many industries in the near future.