Ally Winning, European Editor, PSD
Improved energy storage is possibly the Holy Grail of the industry at this particular time for a variety of reasons. Designers want to make smaller products, but are limited by battery size; there is an expected shortage of Lithium just as the demand from the electric car market is about to increase dramatically; the full potential of renewable energy sources are being held back by the lack of a good storage option to balance peak generating times and peak demand times; and batteries degrade over time, reducing their capacity. Designers all over the world are trying to find solutions to these challenges and more. Just this month, three different teams put forward their own potential solutions to some of these problems.
Firstly, a team at the Indian Institute of Technology announced that they had developed an iron-ion battery and the results showed promise. If the design can be optimised, the new technology could be a stable, cost-effective alternative to today’s Li-ion technology. The new battery has a low-carbon steel anode, a vanadium pentoxide cathode and uses iron chlorate as an electrolyte. The battery has the potential to be cheaper than Li-ion, while offering better storage and stability. They are also safer, as the design can’t produce dendrites, so there’s no possibility of a short circuit when the energy in the battery is discharged. However there are downside too that the researchers are trying to overcome. Currently the battery is only capable of 150 charge/discharge cycles. It also only has around 2/3 of the energy density of Li-ion batteries.
The second new innovation in battery technology this month came from Helmholtz Institute in Ulm, where researchers have also made a breakthrough in replacing Lithium with another element – this time Calcium. Calcium is more abundant than Lithium, but development of Calcium based batteries has been held up due to the lack of a suitable electrolyte. The researchers’ breakthrough was the synthesis of a new chemical that has the highest conductivity of any potential electrolyte so far, as well as being able to conduct ions at a higher voltage than previously discovered electrolytes. The new material was made by reacting a calcium compound with a fluorine compound, producing a calcium salt. Calcium batteries built with the new electrolyte may prove safer and cheaper than Lithium based ones, but time will tell if the breakthrough can be commercialised.
The last new technology I read about this month came from a more familiar source on a more familiar technology. A team at Tesla have published a paper that shows their testing results on an “excellent moderate-energy-density lithium-ion pouch cell chemistry”. The tests have been ongoing for some years, and the researchers claim that the new cells have the potential to power an electric vehicle for over a million miles and last at least two decades in grid energy storage.
The challenges facing the battery industry won’t be solved overnight, but teams across the world are making breakthroughs all the time and eventually these challenges will be overcome.