Recently, Science published a paper on the battery. If the lithium battery is fully charged, the battery will lose 5% if it is not used for one month. If it is an aluminum air battery, it may lose 80% due to corrosion of aluminum. However, the researchers developed a new type of aluminum air battery, which lost only 0.02% a month, and the progress was quite obvious. In short, the new battery is five-fifths lighter and half smaller than a conventional battery.
Between the negative electrode of the battery and the positive electrode, there is generally a liquid electrolyte. When the ions move from the positive electrode to the negative electrode, the electrolyte collects electrons to form an electric current. In an aluminum air battery, the positive electrode is aluminum and the negative electrode is air. Because the air can be extracted from the environment, the aluminum resources are abundant, the weight is light, and the price is cheap, so the future of the aluminum air battery is bright.
Unfortunately, the electrolyte will corrode the aluminum after mixing and will corrode when used. If a non-corrosive electrolyte is used, the battery performance will be degraded. When the battery is re-used and the electrolyte is extracted, it will be found to be unusable because aluminum is hydrophilic (absorbent). The researchers found a solution: rinse the electrolyte with oil.
Between the positive and negative electrodes, the new battery has a thin film, and the two poles of the battery are filled with electrolyte. Once the battery is no longer in use, the oil will flush near one pole of the aluminum, which will protect the aluminum because the electrolyte has a lot of water and it cannot mix with the oil. When we use the battery again, the oil is replaced by the electrolyte. Because the oil does not melt in aluminum, there is no oil left.
The researchers tested the batteries under semi-realistic conditions. They used up a small portion of the battery, then placed the batteries unused, waited a day or two, and repeated the previous process. This test is somewhat similar to the use of urban electric vehicles. The researchers found that the battery lasted for 24 days and was eight times longer than traditional lithium-ion batteries.
Can aluminum air batteries replace lithium batteries in the next few years? No, no. There are some complications to solve when charging the battery, so the original aluminum air battery may not be a rechargeable battery, or the number of times of charging is small. There is also a possibility that the battery can be easily replaced. In the service station, the robotic arm takes the car battery out and replaces it with a fully charged battery so that we can charge it with more complicated mechanical methods.
One more thing to say is that the aluminum air battery does not seem to be shared with the lithium battery. In a hybrid car, gasoline can be shared with the car. However, we can extend the cruising distance with an aluminum air battery. When the owner forgets to charge the main battery, the aluminum air battery can be temporarily used. As one researcher puts it, the future of aluminum air batteries is bright. He said: “You can use it, then drive the car into the driveway, stop for a month, then start the car, the battery still has a lot of power.”