Greg Less, the technical director at the University of Michigan’s Battery Lab, says that Manthiram’s cathode material “shows great promise.” He says there’s still more testing that needs to be done to address problems seen with other similar cathode chemistries, such as the tendency for manganese to dissolve at elevated temperatures, but that the results from the initial tests of the battery are encouraging. “A cobalt-free alternative that can compete with cobalt-containing electrodes is very exciting,” Less says.
To make it happen, Manthiram and his team used specialized techniques to mix the ingredients just so at the nanoscale. This involves pumping solutions containing the nickel, manganese, and aluminum ions into a reactor where they’re mixed with another solution that combines with the metal ions. The result is a finely mixed powder of metal hydroxides that are baked with lithium hydroxide to create the material used for the cathode. The pumping rates and temperatures must be precisely controlled throughout the process to ensure that the resulting cathode material has the right structure and composition. “It took a good knowledge of the basic chemistry to design the cathode composition,” says Manthiram. “And we found a way to control the process so you can have atomic-scale mixing.”
Once Manthiram and his team mixed these elements together, they put the cathode in an experimental lithium-ion pouch cell with a conventional graphite anode. During tests, they found that its performance matched that of commercially available lithium-ion batteries with cobalt cathodes at different charging rates and across hundreds of charging cycles. Although the cobalt-free cathode had a slightly lower energy density, meaning it could store fewer lithium ions, Manthiram believes this gap can be closed by further refining its chemistry.
In the meantime, he’s focused on taking the battery out of the lab and into the real world. He recently founded TexPower to commercialize the cathode, and he says that it should be easy to integrate it with existing battery manufacturing processes. It could be used in batteries for a range of applications, such as consumer electronics, electric vehicles, and storage for the energy grid.
Manthiram hopes that his cobalt-free cathode will hit the market within a few years. And he’s not the only one. A startup called Sparkz recently licensed a cobalt-free cathode from the Department of Energy’s Oak Ridge National Laboratory to commercialize the technology. More established players like Panasonic are racing to reduce the cobalt content in their batteries. Elon Musk has wanted cobalt-free batteries in Teslas for years, and many industry analysts expect him to announce a breakthrough in low-cobalt lithium-ion cells during the company’s “Battery Day” event next month.
Still, cobalt cathodes may be around for a while, says David Weight, the former president and current advisor of the Cobalt Institute, a nonprofit trade group representing producers. Aside from the stability and performance benefits that the metal gives lithium-ion batteries, the companies manufacturing them have spent years and billions of dollars perfecting their cathode chemistries. That means that any new player will have to overcome a lot of industry inertia. “We have to look a long way in the future before chemical systems that don’t require cobalt can become a commercial reality,” Weight says. “The move to a brand-new technology won’t be overnight. Cobalt will be in batteries for the foreseeable future.”
A recent report from the World Bank forecasts that cobalt production will have to increase 500 percent in the next few decades to meet the growing demand for lithium-ion batteries. The DRC won’t be able to meet this demand on its own, and Weight says that there are several cobalt prospecting ventures underway around the world. The biggest cobalt deposits are found on the seafloor, although deep-sea mining remains a contentious issue. But even if supply turns out to be a nonissue, cobalt-free cathodes can still make lithium-ion batteries cheaper, less toxic, and more ethical than ever before.
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