By focusing on the way lithium moves between the two electrodes, scientists in the Netherlands have come up with a new battery design that promises much faster charging rates. The architecture incorporates specialized channel structures that enable a greater flow of lithium ions, which the team hopes can help improve the grid storage capability of renewable energy.
The research was carried out by scientists at the University of Twente and focuses on a relatively new class of materials called niobium tungsten oxides (NbWO). These are seen as promising candidates to replace the graphite used as the negative electrodes in today’s lithium-ion batteries, as they allow lithium ions to flow through them at much greater rates.
In 2018 we looked at a study from the University of Cambridge in which scientists developed and tested a battery with large pillar-like particles of NbWO, which allowed the lithium ions to travel in larger quantities and with greater freedom. The University of Twente team has taken a different approach, exploring what happens when these particles are reduced to the nanoscale size.
The team approached this by calcinating NbWO, or heating it to high temperatures in an oven, to produce tiny nanoparticles measuring tens or hundreds of nanometers in size. One of the features of these nanoparticles is an ability to conduct lithium ions at their boundaries, in effect creating a lot more exits for them to take as the travel through the battery.
Through its testing, the team found that these downsized, nanostructured particles performed impressively, writing, “the results demonstrate that downscaling below 100 nanometers significantly enhances the lithiation dynamics of niobium tungsten oxide. Furthermore, it suggests that the grain boundaries of Nb18W16O93 have significant influence to the fast lithiation process.”
While the results are promising, the team sees the technology finding serving specific uses, at least to begin with. The design wouldn’t be suitable for electric cars, the researchers note, as it would require too big a battery pack. Where it could prove valuable, however, is in some “peak shaving” scenarios, where an over- or under-abundance of grid energy from renewable sources requires batteries to be discharged or charged quickly to help manage the load.
The scientists see other possibilities in using the technology for batteries that power heavy machinery, but for now are working to fine tune the electrode by investigating its optimal size.
The research was published in the Journal of Power Sources.
Source: University of Twente
