Lithium-iron disulfide batteries are a kind of lithium primary. Since lithium-iron disulfide batteries have an operating voltage platform of 1.5V, they have interchangeability with alkaline batteries, Ni-MH batteries having the same size. In addition, lithium-iron disulfide batteries have lighter weigh, superior leakage resistance, greater service advantage at low temperature than alkaline batteries, so they will gradually become the best power supply for portable electronic products.