The “N” in NIMH stands for “nickel-metal hydride,” a type of battery that can store more energy than a conventional alkaline battery. The nickel-metal hydride is a chemical compound used in lithium batteries. It's usually used to power small, high-drain devices such as digital cameras and video game controllers. The. So, you have a pile of used AAA batteries you need to test before you can use them. You could test them one by one with a voltmeter, but that will take forever. A more. NiMH stands for Nickel Metal Hydride and is a new type of internal rechargeable battery. Compared to Nickel Cadmium (NiCd), NiMH batteries are lighter, less toxic,. When you are reading this, you are probably using an electronic device having a battery. The batteries may be rechargeable, or they may be disposable. These.