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Five Things to Know About Lithium-Ion Batteries
The lithium-ion battery inside your phone or computer is what makes the electric device hum. Check out Groupon's overview of how that cell provides the juice you need to read this right now.
1. Like every battery, lithium-ion cells consist of a cathode (+) and anode (-) separated by another material and suspended in an electrolyte as a conductor. The materials used for the cathode and anode determine the battery's performance and voltage.
2. Lithium is probably the best battery material in existence. The lightest of all metals, lithium also has the greatest electrochemical potential. From when the initial experiments began in 1912, it took six decades for the first nonrechargeable lithium cells—such as the robot medicine we've mistaken for watch batteries—to become commercially available.
3. But rechargeable batteries can't use actual lithium. For all its power, lithium is also incredibly unstable, so cycling charges through a lithium anode is too dangerous to be practical. Because of this, lithium batteries let lithium ions flow between the electrodes, producing a voltage of around 3.7 volts—more than double the output of a typical AA alkaline battery.
4. Batteries require different materials for different tasks. Laptops and cell phones might use lithium-cobalt cathodes, which operate at limited power and a consistent voltage. Medical devices, however, might add nickel and manganese to the cathode for greater power and reliability.
5. Don't let your phone charge get to 0%—or even 100%. Both extremes put unnecessary stress on a battery cell. Ideally, lithium-ion batteries should operate between 20 percent and 80 percent capacity. This prevents the battery from becoming over- or undercharged and maximizes the number of potential discharge cycles.