The two most important battery technologies today are NiMH (Nickel Metal-Hydride) and Li-ion  (Lithium-Ion). The two technologies are very similar in their resulting capacities and energy output with minor differences in how they discharge. Lithium-ion camera batteries are the most effective batteries today as lithium has the lowest density of any of the metals on the periodic table and it is also the lightest metal. Interestingly for us, lithium is used in strengthening alloys used in airplanes.
NiCdSome camera manufacturers still use (NiCd) Nickel-Cadmium rechargeable batteries. NiCd batteries dominated the landscape of modern electronics rechargeable batteries. The main advantage of this type of canon camera battery is the high current drain it is capable of withstanding. NiCd batteries are commonly used in applications requiring sudden high bursts of energy such as motors. NiCd batteries are also widely available and prices have dropped considerably in the last few years. Negative traits such as "memory effect" and temperature sensitivity have caused manufacturers to select newer more expensive technologies.
Memory effectA NiCd battery can exhibit this effect when charged and discharged numerous times to the same charge state (both depleted and charged). If discharged to a certain level and not fully drained, as the battery reaches the last drainage level it will show a decrease in output voltage. This means the device being powered can suddenly stop operating.
Temperature sensitivityThis is a two-fold problem. NiCd sony camera batteries perform poorly as temperature increases. The chemical reaction of the Cadmium and Nickel produces more heat as more current is needed. This can lead to battery damage and even fire and destruction of the device being powered.
The use of Cadmium is also not good for the environment. Cadmium is a heavy toxic metal which must be disposed of carefully.
NiMH
Nikon's NP-E3 NiMH battery.
Most consumer cameras today use NiMH batteries. This technology literally eliminates the drawbacks of NiCd technology by having no adverse memory-effect and can also withstand higher temperatures without damage. However the cost of NiMH batteries is higher due to the cost of the metals used.
Advantages and DisadvantagesNickel Metal-Hydride batteries also have a higher energy to density ratio which means you get higher capacity in the same space. They also have a better discharge curve than NiCd and Alkaline batteries especially under high current drain. NiMH batteries also have a longer lifespan than NiCds and are safer for the environment. NiMH is currently the most widely used high end battery technology, widely used now in modern Digital Cameras and Electric Vehicles.
Some disadvantages are a higher self-drain rate than NiCds and when over-discharged, polarity reversal can occur damaging the battery and causing it to fail permanently.
Li-ionLithium-Ion technology is by far the most advanced battery technology today. Li-ion batteries have higher capacity, no memory effect, rechargeable over a longer lifespan and are more durable than any other technology. The only disadvantage being a much higher cost than competing technologies.
It is more widely used in small electronic devices such as cell phones due to the smaller sizes and the need for longer battery life in the smallest possible space.
NiCdSome camera manufacturers still use (NiCd) Nickel-Cadmium rechargeable batteries. NiCd batteries dominated the landscape of modern electronics rechargeable batteries. The main advantage of this type of canon camera battery is the high current drain it is capable of withstanding. NiCd batteries are commonly used in applications requiring sudden high bursts of energy such as motors. NiCd batteries are also widely available and prices have dropped considerably in the last few years. Negative traits such as "memory effect" and temperature sensitivity have caused manufacturers to select newer more expensive technologies.
Memory effectA NiCd battery can exhibit this effect when charged and discharged numerous times to the same charge state (both depleted and charged). If discharged to a certain level and not fully drained, as the battery reaches the last drainage level it will show a decrease in output voltage. This means the device being powered can suddenly stop operating.
Temperature sensitivityThis is a two-fold problem. NiCd sony camera batteries perform poorly as temperature increases. The chemical reaction of the Cadmium and Nickel produces more heat as more current is needed. This can lead to battery damage and even fire and destruction of the device being powered.
The use of Cadmium is also not good for the environment. Cadmium is a heavy toxic metal which must be disposed of carefully.
NiMH
Nikon's NP-E3 NiMH battery.
Most consumer cameras today use NiMH batteries. This technology literally eliminates the drawbacks of NiCd technology by having no adverse memory-effect and can also withstand higher temperatures without damage. However the cost of NiMH batteries is higher due to the cost of the metals used.
Advantages and DisadvantagesNickel Metal-Hydride batteries also have a higher energy to density ratio which means you get higher capacity in the same space. They also have a better discharge curve than NiCd and Alkaline batteries especially under high current drain. NiMH batteries also have a longer lifespan than NiCds and are safer for the environment. NiMH is currently the most widely used high end battery technology, widely used now in modern Digital Cameras and Electric Vehicles.
Some disadvantages are a higher self-drain rate than NiCds and when over-discharged, polarity reversal can occur damaging the battery and causing it to fail permanently.
Li-ionLithium-Ion technology is by far the most advanced battery technology today. Li-ion batteries have higher capacity, no memory effect, rechargeable over a longer lifespan and are more durable than any other technology. The only disadvantage being a much higher cost than competing technologies.
It is more widely used in small electronic devices such as cell phones due to the smaller sizes and the need for longer battery life in the smallest possible space.