Researchers in Germany have developed a lithium-ion metal cell that reaches 560Wh/kg.
The energy density— based on the total weight of the active materials— comes from a nickel-rich cathode that enables storage of high energy per mass.
The scientists are from Helmholtz Institute Ulm (HIU) of Karlsruhe Institute of Technology (KIT) in Germany reports the cell has shown the battery’s capacity remains 88% after 1,000 cycles due to its ionic liquid electrolyte.
Researchers first used a cobalt-poor, nickel-rich layered cathode (NCM88) with the commonly used, commercially available organic electrolyte (LP30), but the cell’s storage capacity decreased as the number of cycles increased with this combination.
By using a dual-anion ionic liquid electrolyte (ILE) the NCM88 cathode reached 560Wh/kg.
The combination of cathode and electrolyte was reported in the journal Joule.
Its initial storage capacity is 214mAh g-1 of the cathode material. The average Coulombic efficiency, i.e., the ratio between discharge and charge capacity, is 99.94%.
Professor Stefano Passerini, director of HIU and head of the electrochemistry for Batteries Group, said: “In the electrolyte LP30, particles crack on the cathode. Inside these cracks, the electrolyte reacts and damages the structure.
“In addition, a thick mossy lithium-containing layer forms on the anode.”
For this reason, the scientists used a non-volatile, poorly-flammable, dual-anion ionic liquid electrolyte (ILE) instead to reduce structural modifications on the nickel-rich cathode
Image: With a promising combination of cathode and electrolyte, the HIU researchers aim to make a very high energy density possible. (Photo: Amadeus Bramsiepe, KIT)