Trends in advanced batteries and key materials in the new century

Our way of life is greatly changing due to rapidly developing information technology (IT) and the serious problems in our ecosystem caused by the increased heating of the environment and the amount of exhaust CO2 as the result of rapid increases in fuel consumption. Batteries play an important role not only in assisting us in our new IT society but suppressing the damage to the ecosystem by improving of the energy efficiency. In this article, the technological trends of Li-ion and Ni-MH secondary batteries and fuel cells will be described in connection with the advanced materials and fabrication processes utilized for realizing these batteries.