Lithium-ion batteries are based on innovative technology that uses lithium as a component of the electrodes. They differ fundamentally from nickel-based batteries and, at 3.6 volts, have a cell voltage three times that of a nickel cadmium battery. You need fewer battery cells, making the power tool smaller and lighter, or more powerful if it remains the same size. In addition to a significantly lower self-discharge, lithium-ion batteries have no memory effect, in contrast with nickel cadmium batteries