Lithium-ion capacitor

A lithium-ion capacitor (LIC or LiC) is a hybrid type of capacitor classified as a type of supercapacitor. It is called a hybrid because the anode is the same as those used in lithium-ion batteries and the cathode is the same as those used in supercapacitors. Activated carbon is typically used as the cathode. The anode of the LIC consists of carbon material which is often pre-doped with lithium ions. This pre-doping process lowers the potential of the anode and allows a relatively high output voltage compared to other supercapacitors. In 1981, Dr. Yamabe of Kyoto University, in collaboration with Dr. Yata of Kanebo Co., created a material known as PAS (polyacenic semiconductive) by pyrolyzing phenolic resin at 400–700 °C. This amorphous carbonaceous material performs well as the electrode in high-energy-density rechargeable devices. Patents were filed in the early 1980s by Kanebo Co., and efforts to commercialize PAS capacitors and lithium-ion capacitors (LICs) began. The PAS capacitor was first used in 1986, and the LIC capacitor in 1991. It wasn't until 2001 that a research group was able to bring the idea of a hybrid ion capacitor into existence. A lot of research was done to improve electrode and electrolyte performance and cycle life but it wasn't until 2010 that Naoi et al. made a real breakthrough by developing a nano-structured composite of LTO (lithium titanium oxide) with carbon nanofibers. Nowadays, another field of interest is the Sodium Ion Capacitor (NIC) because sodium is much cheaper than lithium. Nevertheless, the LIC still outperforms the NIC so it's not economically viable at the moment. A lithium-ion capacitor is a hybrid electrochemical energy storage device which combines the intercalation mechanism of a lithium-ion battery anode with the double-layer mechanism of the cathode of an electric double-layer capacitor (EDLC). The combination of a negative battery-type LTO electrode and a positive capacitor type activated carbon (AC) resulted in an energy density of ca.