3.7-volt batteries come in many different form factors and are commonly used in portable electronic devices including cellphones, digital cameras, camcorders, handheld gaming devices and electronic cigarettes. The most common 3.7-volt batteries are lithium-ion batteries, which come in flat and cylindrical form factors.
Li-ion batteries, or lithium-ion batteries, are rechargeable. Lithium ions move from the negative electrode to the positive electrode when the battery is discharging and in the opposite direction when charging.
Apart from their common use in portable electronics, Li-ion batteries are also used in portable power tools, such as cordless drills, sanders and saws, and in electric vehicles.