Alkaline vs Lithium Batteries
Batteries are everyday needed household necessities. Although most of the equipments are now directly working with the electricity, a lot of other small or portable devices need batteries. For example, alarm clocks, remote controllers, toys, torches, digital cameras, radios are working with the current supplied by a battery. Using batteries are safer than using main electricity directly. There are lots of batteries under various brand names in the market today. Except the brand names, these batteries can be divided into two types according to the chemistry of generating electricity.
Alkaline battery is an electrochemical cell with an anode and a cathode which produces electricity through a chemical reaction. The anode or the negative electrode of the alkaline battery is made of zinc powder. And the positive terminal or the cathode is made of manganese dioxide. The electrolyte in the battery is potassium hydroxide. Following are the two half reactions taking place in the electrodes.
Zn (S) + 2 OH- (aq) → ZnO (s) + H2O (l) + 2e
2 MnO2 (s) + H2O (l) + 2e → Mn2O3 (s) + 2 OH- (aq)
The usual voltage for an alkaline battery is 1.5 V and voltage can be increased by having a series of batteries. There are different sizes of the battery (AA, AA-, AAA, etc), and the current produced by the battery depends on the size. For example, AA battery produces 700 mA current. Now there are rechargeable alkaline batteries also. However, normal alkaline batteries have to be disposed after a certain period of usage. There is about 1 mV voltage left in the battery when it is fully discharged. Since alkaline batteries are not so toxic, they can be disposed with domestic waste, but it is always good to be careful when disposing. Alkaline batteries may have a chance of leaking the inside potassium hydroxide electrolyte which causes skin and respiratory irritation. So when the outer shell of the battery is damaged, those batteries should not be used.
In Lithium battery, lithium or lithium compounds are used as the anode. Lithium batteries produce voltage 1.5 V or more than that depending on the design. These should be disposed after using and cannot be recharged. Lithium batteries are used in small devices like watches, calculators, car remotes. Further, they can be used in powerful large devices like digital cameras. Since lithium batteries are toxic, they should be handled and disposed with care.
What is the difference between Alkaline and Lithium Batteries?
• The life time of lithium batteries is much higher than the alkaline batteries.
• Lithium batteries are easy to use. They can be used in either very hot or cold conditions where alkaline batteries cannot be used. Therefore, lithium batteries can be used for outdoor activities also, compared to the alkaline batteries.
• Lithium batteries are lighter in weight than alkaline batteries. This makes lithium batteries ideal for the portable devices.
• Usually lithium batteries give 1.75 V or more whereas alkaline batteries give 1.5V. Thus, the power is higher in the lithium battery. (Lithium battery gives a brighter light beam when used in a torch)
• Alkaline batteries are less expensive than the lithium batteries.
• Lithium batteries are toxic, and alkaline batteries are not so. Therefore, lithium batteries should be disposed with care.
• There is a rechargeable alkaline battery type available now. But there are no rechargeable lithium batteries.