The assembly and testing of a rechargeable 3 V lithium-ion battery in the common 2032 coin cell format is demonstrated in a classroom environment without the use of expensive and complex air-free equipment. The procedure has been developed to eliminate the use of highly toxic materials and flammable solvents, can be accomplished in 15 min, and is designed to be as inexpensive, safe, and simple as possible. The battery can be repeatedly charged with a cheap USB-powered charger and can be used to power an LED tea candle or similar device. A stopwatch and multimeter can be used to estimate the capacity and voltage of the battery. This demonstration offers a memorable, real-world application of electrochemical principles and gives students practical insight into the chemistry and construction of a lithium-ion battery.