A team of researchers affiliated with multiple institutions in China has
increased the speed of charging a lithium-ion battery by adding a copper
coating and nanowires to its anode to improve ordering. Their study is
published in the journal Science Advances.
Industry analysts have suggested one of the characteristics holding back the
widespread changeover from gas powered vehicles to those running on
batteries is the time it takes to recharge the battery. A Tesla vehicle, for
example, has been found to take nearly an hour to charge its battery from
40% to 80%. In this new effort, the researchers have looked into one of the
main obstacles to faster charging and have modified a battery to solve the
problem.
One of the major bottlenecks in speeding up charging is the battery's anode.
Most are made of graphite and are constructed in a non-ordered slurry, which
the researchers note, is not an efficient means of passing along current.
They also point out that in addition to the way the materials in them line
up, there is the issue of the gap size between them.
To overcome this problem, they first ran particle-level theoretical models
to optimize the spatial distributions of different sized particles and
electrode porosity. They then took what they learned from the models to make
changes to a standard graphite anode. They coated it with copper and then
added copper nanowires to the slurry. They then heated and then cooled the
anode, which compressed the slurry into a more ordered material.
They affixed the anode to a standard lithium-ion battery and then measured
the amount of time it took to charge. They found they were able to charge
the battery to 60% in just 5.6 minutes (as opposed to 40% for a control
battery with no alterations) and to 80% in just 11.4 minutes. They did not
test how long it would take to charge to 100% because doing so is not
recommended for such batteries. The researchers did not reveal if they had
developed estimates for how much adding the copper to the anodes would add
to the price of the batteries.
Reference:
Lei-Lei Lu et al, Extremely fast charging lithium ion battery enabled by
dual gradient structure design, Science Advances (2022).
DOI: 10.1126/sciadv.abm6624.