At present, the battery has been used in more and more areas. In most cases, we only know the elements of the battery, nickel, chromium, etc., which are known to a little more people. Now, let's talk briefly about the nickel-metal hydride battery. The ingredients.
The domestic nickel-metal hydride battery is a low-pressure nickel-hydrogen battery, with Ni(OH)2 as a positive electrode, a hydrogen storage alloy as a negative electrode, and an alkaline aqueous potassium hydroxide solution as an electrolyte. The specifications of nickel-metal hydride batteries are generally the same as those of nickel-cadmium batteries. There are many differences in the performance indicators, but nickel-metal hydride batteries have their own unique advantages, the most important manifestation is the high specific energy density of nickel-metal hydride batteries (that is, the same volume of batteries, nickel-metal hydride batteries than nickel The cadmium battery has a larger capacity. In theory, the nickel-metal hydride battery is 1.5-2 times more than the energy density of the nickel-cadmium battery; there is also a nickel-metal hydride battery with good environmental protection, and the nickel-metal hydride battery does not use the metal "cadmium" nor toxic substances. Does not pollute the environment; there are basically "memory effects" of nickel-metal hydride batteries. Of course, it does not contain zinc or manganese.
NiMH battery chemical composition:
The "metal" portion of a nickel-metal hydride battery is actually an intermetallic compound. Many kinds of intermetallic compounds have been used in the manufacture of nickel-metal hydride batteries. They are divided into two major categories. The most common is AB5, A is a mixture of rare earth elements (or) plus titanium (Ti); B is nickel (Ni), cobalt (Co), manganese (Mn), (or) aluminum ( Al). In some high-capacity batteries, the “multi-composition” electrode is mainly composed of AB2, where A is titanium (Ti) or vanadium (V), and B is zirconium (Zr) or nickel (Ni). Some Cr, Co, Fe, and Mn. All these compounds play the same role: they can be converted into metal hydrides. When the battery is charged, hydrogen ions (H+) in the potassium hydroxide (KOH) electrolyte are released and absorbed by these compounds to prevent the formation of hydrogen (H2) to maintain the internal pressure and volume of the battery. When the battery is discharged, these hydrogen ions return to their original place through the reverse process