Abstract:
The generation of green energy in the form of electricity, from renewable
sources such as wind and sun are in rapid progress. Nevertheless, the sun doesn’t shine all
the day and wind doesn’t blow under command. Therefore, mastering energy storage is
crucial in order to provide electricity when and where it is needed. In fact, using
electrochemical energy storage devices is the best way to store energy (into its chemical
form) and converted into electricity. Among these electrochemical devices, one can
mention; Lithium ion batteries, fuel cells and electrochemical capacitors (ECs) (also called
supercapacitors). The latter which use ions adsorption, from electrolyte, on the surface of
their active material, can provide higher power density and longer operating life time than Li
ions batteries. Nowadays, ECs can bridge between Li-ions batteries and conventional
capacitors in term of energy and power densities; Capacitors which recharge in seconds and
last for thousands cycles, ECs can find application as power source in electric vehicles and
distributed energy system in solar cells or wind power stations [1]. Miniaturisation of the
ECs in the form of packed films can also be integrated on the chip along the circuit they
power for use as power source in portable electronic devices. In this contribution, I will
introduce the stat of art of ECs, their applications and challenges to build a better ECs device.
In particular, the development of nano-stuctured materials (including transition metal oxides
or nitrides, polymers, carbon and so on…) as active material in ECs will be highlighted
