By Irina Slav
The battery world is a fascinating place to be right now. There is so much innovation going on as the world sets course towards a battery-powered future. The difficulty for observers is knowing what is a legitimate breakthrough and what is just hype that will never be commercialized.
Still, some undeniable trends have emerged, and chief among them is that lithium ion battery improvements are nearing their limit. This is a natural development. It was bound to happen, especially given the pace of improvement in this dominant type of battery over the last decade or so.
The main problems with Li-ion batteries remain: relatively high cost, insufficient energy density in a context of ever-higher energy density demand, and safety issues because of the liquid electrolyte these batteries use. The batteries of tomorrow seek to solve these problems, and some battery researchers report success (although these alternatives have yet to enter the commercial production stage that would prove they could compete with the Li-ion hegemon).
One of these alternatives is a battery that uses silicon for the anode instead of graphite, increasing the energy density of the battery. In an overview of the latest in batteries for The Enterprise Project, Stephanie Overby quotes energy researcher Chloe Holzinger from Lux Research as saying, “Silicon offers a potential tenfold increase in capacity over incumbent graphite, leading to a higher specific energy. Higher specific capacity could result in lower costs if material costs are not too high.”
Yet this particular improvement is currently focused on consumer electronics, as is a lot of battery innovation, such as Ionic Materials’ solid polymer battery that addresses the liquid electrolyte issues of lithium ion batteries, chief among them flammability. Speaking to CNBCrecently, the CEO of the company, Mike Zimmerman, said in addition to eliminating the flammability problem, the Ionic Materials batteries, featuring a polymer for an electrolyte, are also more durable and have a greater capacity than their chief competitor. These batteries do hold promise for EVs and energy storage as well as consumer electronics, as long as the cost is low enough; and it will be, Ionic Materials says.
In other news, another company, NantEnergy, last month announced a breakthrough: the cost of its air breathing zinc battery broke the US$100 per kWh barrier and will now begin to be deployed on a large scale. The latter part of this announcement is the significant one: there have been lots of reports about the battery of the future but all of them have come from the lab. If someone’s talking about large-scale deployment, then there may be something to this battery that’s being talked about. In this case, it is a battery that uses air for a cathode and zinc for an anode, which means it has a much lower carbon footprint than lithium ion batteries and is safer.
Then there are the sodium ion batteries that recently got their first commercial deployment at a sewage pumping station in Sydney. With sodium being cheaper than lithium, this type of battery has been a natural competitor despite the fact that it has significantly lower energy density than lithium ion batteries.
With all this said, lithium-containing batteries are yet to be dethroned. Innovation may be reaching its limits in this area, but it’s not there yet. The latest here is nanotubes. Researchers from Rice University recently reported the addition of a coating of nanotubes to the anode of a lithium metal battery prevents the so-called dendrites from forming and ultimately killing the battery. These dendrites, or metal whiskers, have been a major obstacle for the wider adoption of lithium metal batteries. With that solved, they might get a serious push, which will be good news: lithium metal batteries are more energy dense than their li-ion cousins.