Dahn Lab formulates 1 million-mile Li-ion battery: How and why

September 25, 2019 | Case Study

In a benchmarking paper, the Dahn Lab at Dalhousie University achieved 4,000 cycles with NMC 532/graphite that effectively triples the typical lifetime expected from similar Li-ion cells. Researchers employed single-crystal NMC 532 coated with TiO₂ to stabilize the cathode, an artificial graphite anode, and electrolyte additives like vinylene carbonate and ethylene sulfate to achieve the long cycle life. All testing materials were procured from commercial suppliers: cathode powders from Li-Fun Technology, artificial graphite from Kaijin, and electrolytes from BASF and Shenzen Capchem. Cells were assembled using typical techniques, save for a vacuum drying step prior to electrolyte filling. Dahn said the 4,000 cycles translated to a vehicle service life in excess of 1 million miles; with a cell-level energy density of roughly 800 Wh/L, there is no longer a trade-off between long cycle life and high energy density in Li-ion batteries.