These are rechargeable batteries, which can be recharged after they are used up. Nickel-cadmium batteries have a memory effect, so you must use up the power in the battery before charging each time. Memory of nickel-metal hydride batteries The effect is much smaller and can be charged at any time. Lithium batteries have no memory effect and can be charged at any time. Among these types of batteries, lithium batteries have the largest volume-to-capacity ratio, which means that for batteries of the same size, lithium batteries have the most power. It is also the best battery currently. Lithium-ion battery is a type of lithium battery.