Nanowires and Viruses Combine to Create High-Capacity Batteries
While lithium-ion (Li-ion) batteries have managed to elevate hybrid vehicles into a significant segment of the automotive market, all-electric vehicles using that same battery technology have languished as a niche product. Li-ion batteries just don’t have the long charge life or short recharging capabilities that would make all-electric vehicles a good fit for most people’s driving habits. (It also doesn’t help the marketing image of automakers when these all-electric vehicles burst into flames.)
Marketing considerations aside, the recent demise of a few high-profile nanotech companies that tried to make Li-ion batteries for all-electric vehicles may indicate fundamental problems with the current approach. Maybe we need a different battery technology to make all-electric vehicles mainstream.
This realization already began to sink in with the research communities a few years back, and I started noticing more research into Lithium-air batteries. Lithium-air batteries use the oxidation of lithium at the anode and the reduction of oxygen at the cathode to create a current. This battery design has promised up to 10 times as much energy as a lithium-ion battery at the same weight, giving them an energy density equal to that of gasoline.
Greater storage capacity certainly helps solve one EV limitation, but if a battery technology is going to displace fossil fuels, it also needs to recharge as quickly as—or on par with—filling up a car at gas station. Earlier this year, researchers at Massachusetts Institute of Technology (MIT) and Sandia National Laboratory peered into the lithium oxidation process of Li-air batteries and saw a possible way to speed up battery recharging.
Now researchers—again from MIT—have made progress on both fronts. They took nanowires made of manganese oxide (which is often used as the material for the cathode of Li-air batteries) and coated them with man-made viruses. These viruses create a larger surface area that improves the reaction between the lithium and oxygen, resulting in a greater storage capacity and a faster rate of recharging. A video describing the technology can be seen below.