A team of researchers from various institutions in China has increased the charging speed of a lithium-ion battery by adding a copper coating and nanowires to its anode to improve control.
Industry analysts have suggested that one of the characteristics holding back the widespread shift from gasoline-powered to battery-powered vehicles is the time required to recharge the battery. A Tesla vehicle, for example, takes almost an hour to charge its battery from 40% to 80%. In this new effort, researchers analyzed one of the main obstacles to faster charging and modified a battery to solve the problem.
One of the main bottlenecks for speeding up charging is the battery anode. Most are made of graphite and constructed in an unordered paste, which the researchers say is not an efficient way to pass current. They also point out that in addition to the way the materials are aligned there, there is the problem of the size of the gap between them.
To overcome this problem, they first ran theoretical particle-level models to optimize the spatial distributions of particles of different sizes and the porosity of the electrodes.
They then used what they learned from the models to make modifications to a standard graphite anode. They coated it with copper, then added copper nanowires to the paste. They then heated and cooled the anode, which compressed the paste into a neater material.
They placed the anode on a standard lithium-ion battery and measured the charging time.
They found they could charge the battery to 60% in just 5.6 minutes (compared to 40% for an unmodified control battery) and 80% in just 11.4 minutes. They have not tested 100% charge time as it is not recommended to do so with these types of batteries. The researchers did not reveal whether they made any estimates of the amount of copper in the anodes that would drive up the price of the batteries.
More information: www.science.org (English text).