Ultrafast charging of batteries using nickel niobiate anode materials
Above: Nickel niobate has a regular and open crystal structure, with many channels for charge transport.
By using a fully new material, nickel niobate, for the anode of lithium-ion batteries, the charging speed can be improved tenfold, according to researchers of the University of Twente.
Compared to current norms, there is much scope for improving battery performance whether for electric vehicles or for the electricity grid.
Key measures are faster charging and decharging, or a higher energy density, resulting in more compact and lighter batteries, but often there is some kind of ‘trade-off’ of these two. High-speed chargers on motorways are an example. Not all cars and car batteries are prepared for this.
Consequently, there is a worldwide search for new materials. An important aspect, next to the technical specifications, is drastically improving the sustainability and carbon footprint of battery production.
Now, a new material called nickel niobate (NiNb2O6) appears to have very attractive properties and even after many cycles of ultrafast charging, it returns to its original level. This primarily has to do with its attractive ‘open’ and regular crystal structure, resulting in channels for charge transport that are identical.
This means that it performs better than graphite, the standard anode material. That is an ‘open’ material too, and it is simple. But after some cycles of high-speed charging, it will not return to the original level, or it will even break down.
In the search for alternatives, at the University of Twente, new types of nano-structured materials were investigated. A disadvantage, however, is that sometimes the channels are organized in a more random way. This may even cause deposits of lithium on the anode material, resulting in progressively poorer performance. Manufacturing these materials is a;lso complicated.
But for nickel niobate, a cleanroom infrastructure is not necessary. The manufacturing process is not complicated and is possible without the risk of damaging the anode material, causing battery breakdown or reducing its lifetime.
The high charging and decharging rates do have consequences for the weight and energy density, however. Nickel niobate is more compact than graphite, so it has a higher ‘volumetric’ energy density.
The researchers tested the first full batteries with the new anode material, coupled with various existing cathode materials. They conclude that this version would be ideal for introducing it into an energy grid, in electrically powered machines in that require fast charging and decharging, or in electrically powered heavy transport.
For using it in electrically powered cars, some additional steps still have to be taken. According to , research leader Professor Mark Huijben, the new anode is also suitable for replacing lithium by, for example, sodium.
- The research was done at the Twente Centre for Advanced Battery Technology, part of UT’s MESA+ Institute, in collaboration with the Wuhan University of Technology in China and Forschungszentrum Jülich in Germany.