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.

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.

The combination of a negative battery-type LTO electrode and a positive capacitor type activated carbon (AC) resulted in an energy density of ca.

Bare LTO has poor electrical conductivity and lithium ion diffusivity so a hybrid is needed.

[9] The advantages of LTO combined with the great electrical conductivity and ionic diffusivity of carbonaceous materials like carbon coatings lead to economically viable LIC's.

This step is referred to as "doping" and often takes place in the device between the anode and a sacrificial lithium electrode.

Their main advantage is that it's a way to increase the rate capability of the anode by reducing the diffusion pathways of the electrolytic species.

Different forms of nanostructures have been developed including nanotubes (single- and multi-walled), nanoparticles, nanowires, and nanobeads to enhance power density.

[12] The expected benefit, compared to graphitic carbons, is to increase the doped electrode potential which leads to improved power capability as well as reducing the risk of metal (lithium) plating on the anode.

To maximise the effectiveness of the cathode it should have a high specific surface area and good conductivity.

Another reason for pre-lithiation is that high-capacity electrodes irreversibly lose capacity after the initial charge and discharge cycles.

In general, the anode of LIC's is pre-lithiated since the cathode is Li-free and will not take part in lithium insertion/desertion processes.

For LIC's the electrolyte ideally has a high ionic conductivity such that lithium ions can easily reach the anode.

These are not mentioned very often but they do have their applications and have their own advantages and disadvantages compared to organic electrolytes which mainly comes from their porous structure.

Compared to the electric double-layer capacitor (EDLC), the LIC has a higher output voltage.

As demonstrated in recent studies, LiCs can maintain approximately 50% of their capacity at temperatures as low as -10°C under high discharge rates (7.5C).

This makes LiCs particularly suitable for applications in cold climates or where the temperature fluctuates widely.

One important potential end-use of HIC(hybrid ion capacitor) devices is in regenerative braking.

Regenerative braking energy harvesting from trains, heavy automotive, and ultimately light vehicles represents a huge potential market that remains not fully exploited due to the limitations of existing secondary battery and supercapacitor (electrochemical capacitor and ultracapacitor) technologies.