The rechargeable sealed Nickel Metal Hydride (NiMH) cell absorbs hydrogen in the metal alloy makeup of its negative electrode during charge. As the cell is discharged, the metal alloy releases hydrogen to form water.
The use of the metal alloy is the underlying reason for the high energy density of the NiMH cell compared to other chemistries. NiMH batteries have a long cycle life and good storage characteristics.

Key Features:
Production technology is mature, quality is stable and pretty safe.
Low internal resistance.
Long cycle life over 500 cycles.
Friendly to the environment: No Cadmium, Mercury effect, Lead.

Note: Characteristics can change according to improvements in chemistry or special niche requirements.