In general there are three kinds of batteries for us to use, such as: Nickel-chromium battery; Ni-MH battery; Lithium battery.they are generally expressed as: Ni-Cd NI-CD, Ni-MH NI-MH, Lithium-Ion battery LI,

1. because of their too early age ,there are many headache shortcomings for Nickel Cadmium battery NI-CD ,, such as: bulky, heavy weight, capacity, small, short life, there is memory effect, etc. (useless), and now no longer in use .
2. Ni-MH battery is more environmentally friendly some compared to other battery, , it is also by far the most environmentally friendly battery in the world
3. Li-ion battery could offer important advantages, including a small size, light weight, large capacity, low memory effect, charging time is short, etc.,but you will often see the back of the battery properly abandoned and handling lithium batteries instructions? It will cause environmental pollution. to discard the lithium battery

Now some people may be misunderstanding of lithium battery, they believe lithium batteries can not remember things, in fact , only relatively small memory, it seems not to be very clear. And lithium batteries can be divided into lithium and lithium-ion battery two kinds. Lithium-Ion battery has been in world for a long time ,but it is not safe when used and often might burn, burst when is in charge, perhaps because of the sake of lithium element too active. Then there is an improved lithium-ion batteries,the element of active ingredients is added in lithium so that lithium is really safe .efficient and convenient, while the older Lithium-Ion battery also is eliminated.