The Lithium-ion Battery is here to stay. The 18650 the most popular style
Lithium-ion batteries are constructed from two positive and negative electrodes separated by a liquid chemical electrolyte, such as ethylene carbonate or diethyl carbonate. The chemical composition of this battery limits it to a mostly rectangular shape. Lithium-ion battery capacity decreases over charge cycles and even discharges when not in use, which isn’t ideal. The 18650 size is

