Nickel Metal Hydride — NiMH

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Extremely Alkaline Stable Membranes & Polymers

Aemion™ membranes and polymers are extremely alkaline stable and offer several potential advantages for continued development in next generation NiMH batteries. Its high strength allows for production of ultra-thin films that can be used to coat the electrode to prevent damage during charging and discharging, increasing cycle life. As a separator, the high conductivity could enable reduction in KOH concentration and improve component lifetime. Direct deposition is possible for bipolar cells and the move toward solid state batteries.

NiMH batteries were developed with the advent of stable metal hydrides for storing hydrogen, and largely replaced the nickel cadmium (NiCad) battery. NiCads are extremely rugged, with long cycle lives, and good low-temperature performance; however, they have relatively high levels of self-discharge and cadmium is a toxic metal, making disposal a concern.

NiMH batteries use nickel hydroxide as one electrode and metal hydride in the other, enabling both elimination of toxic cadmium and increased volumetric energy density. Compared to Li-ion batteries, NiMH suffer from comparatively lower mass energy density. However increases in voltage, or reductions in electrolyte volume by migrating to membrane-based solutions has the potential to close the gap and provide distinct advantages.