The need for speed in charging the lithium batteries that power electric vehicles has spurred development of a new electrode material that restructures itself to accelerate the charging process.

As lithium ions travel from the cathode to the graphite-based anode at high charging speeds, lithium metal accumulates on the surface of the anode and degrades battery performance. This plating effect can lead to short circuits, overheating or a fire. The inclusion of niobium pentoxide, a compound much less susceptible to plating, eliminates these performance limitations with a nanostructure that is easily reconfigured into stable configurations.

When embedded in a coin cell and repeatedly charged and discharged, the amorphous niobium pentoxide structure transformed into an ordered, crystalline one that supported faster transport of lithium ions into the anode during charging. This finding points to the material’s promise for fast charging, and other measurements suggest that it can store a large amount of charge.

Transmission electron microscopy images verified the transformation of the electrode material from a disordered arrangement of atoms (left) to an ordered, crystalline structure (right). Source: U.S. Argonne National LaboratoryTransmission electron microscopy images verified the transformation of the electrode material from a disordered arrangement of atoms (left) to an ordered, crystalline structure (right). Source: U.S. Argonne National Laboratory

The disordered-to-crystalline transformation resulted in excellent cycling stability at high charging speeds, with the battery exhibiting a capacity of 225 mAh/g at 200 mA/g across 400 cycles, with a Coulombic efficiency of 99.93%.

Scientists from Boise State University, University of California San Diego, U.S. Argonne National Laboratory and U.S. Pacific Northwest National Laboratory participated in this research, which is published in Nature Materials.

To contact the author of this article, email shimmelstein@globalspec.com