It has been shown thatc urrent works dealing with nanostructured materials aiming at the fabrication of high
efficiency stable SC electrodes are part of a wide area of
investigation into energy storage and transformation.
We intentionally excluded from this review any publications dealing with the use of transition metal oxides and
their composites as SC electrodes although these compositions yielded very high specific capacities. We will publish a
special review for transition metals as SC electrodes.