I have written a number of articles over the past year about new developments with batteries. One was about Graphene and the research undertaken to make this material provide more power and one has been about Lithium-ion batteries – the current mainstay of most mobile technology from cars to mobile phones and laptops.
It is very difficult to extract more power out of a Lithium battery – the recent issues with Samsung mobile phones and the heat provided by my iPhone show that today’s technology use a lot more power than older devices and this means that developers must get more power (or a longer life) from a battery. That is where the research in materials like graphene come into play – could a new material give consumers a long life battery that doesn’t fade over time and can cope with future technologies – and run cooler!
The boffins at MIT (Massachusetts Institute of Technology) have been reworking an old idea. Many of today’s technologies are based on old ideas and the Lithium-air battery has been around in some form for the past 40 years. The theory suggests that this type of battery could hold as much as 4 times the energy per kilogram than a Lithium-ion battery. As it’s name suggests, the battery uses Lithium and air to create the power output, however it is not truly air that is the reactor but one component: oxygen. The problem with air is that the other components cause big problems with the battery namely water vapour and carbon dioxide which damage the battery.
Scientists found this quite quickly, so they developed versions running with pure oxygen, however that didn’t work as planned because oxygen is a gas and to get enough of it into a battery, it needs to be a solid. To use it, it needs to be a gas, so the researchers had to take the gas, convert it to a solid and then reconvert it back to a gas for consumption. This meant high energy consumption to create the battery (not good) and the battery gets damaged when the solid oxygen converts to a gas (bad) and as such makes the whole product unstable for manufacturing and consumer use (very bad and a dead end for profitability).
What the team at MIT have now done is to hermetically seal the battery with Lithium Superoxide (so not really air!) and because this is naturally unstable, they have had to add in a matrix of Cobalt Oxide to stabilise the substance. A liquid electrolyte is used to extract power. When the battery is in use, the electrolyte is absorbed into the matrix and converts to either Lithium Peroxide or Lithium Oxide and these chemical reactions create electrons that move around an internal circuit thus providing the power. Now, when a power supply is connected, the whole process is reversed and the battery is charged up again. The key is that all the Lithium based components are solids which means that less energy is lost when the chemical reactions occur.
Trials show initial success with life and the ability to constantly recharge the battery with minimal loss of capacity. At this stage this new version is still a prototype and needs a lot of testing and evolutions of development. The researchers think that they can get something to market fairly quickly and as such have filed patents and have been talking to car manufacturers presumably to see if any one of them would invest in or licence the end product.
As cars need a lot of energy to power the propulsion systems, air conditioning and dashboard systems, it is vital that the batteries can cope with constant use and charge cycles. These cause heat and we have all heard of Tesla’s catching fire just like mobile phones and laptops. To have a battery system that is cooler to use with a longer life means that full electric cars will become a much more easier decision for many buyers.