For most electronic devices it is better to use NiMH batteries than NiCd batteries.
NiCd batteries use Cadmium, a highly toxic heavy metal, that can damage the environment if not disposed of properly. (They should be recycled not discarded). NiMH batteries usually have a higher capacity than NiCd batteries of the same size. Some people argue that NiCd batteries deliver faster discharge rates than NiMH batteries. While this may be true under certain circumstances, the difference is not relevant when considering power sources for electronic devices like digital cameras or portable music players. (If you are choosing a battery to drive a high torque power screwdriver, then NiCds can outperform NiMH).
NiMH batteries require more sophisticated chargers than those typically used for NiCd batteries. But smart chargers designed especially for NiMH batteries are now readily available.
