For years, lithium-ion batteries have been used in electric vehicles and some communications grid applications. Now, a battery technology startup, Fluidic Energy has developed rechargeable metal-air batteries that can potentially replace that. These batteries can store more energy than lithium-ion and are cheaper.
Metal-air batteries have been commercially available for a long time but they are not rechargeable. These non-rechargeable batteries are often used in hearing aids. Metal-air batteries generate electricity by reacting metal like zinc with oxygen from air.
Recharging the battery was a major challenge. Oxygen needs to be removed to allow zinc metal to form again. However, instead of forming dense, solid zinc metal, it forms a porous structure that takes up more space. Moreover, upon recharging, zinc will also form root-like structures that can short the circuitry within the battery.
Fluidic Energy uses chemical additives to address the porous zinc structure problem, ensuring the zinc forms dense and uniformed layers. The additives however, will evaporate and breakdown over time. Hence, Fluidic Energy developed an inexpensive proprietary ionic liquids that will not evaporate or decompose when the battery is in use.
According to Fluidic Energy’s chief technology officer Cody Friesen, the company also develops air electrodes (a site for air to interact with zinc) that can last five to seven times longer than what is available in the marketing. This will make the batteries cheaper than buying combination of lead-acid batteries and diesel engines that act as backup power supply to telecommunication towers. When the towers are connected to the grid, the metal air batteries can be charged at the same time, eliminating the need for diesel fuel.
Rechargeable metal-air batteries seem to be a good solution for telecommunication towers but it will be some time before the batteries will be used in cars. Friesen says, “We’re not anywhere close to that”.