Four-million-mile battery is now a reality (2024)

These single crystal NMC532/graphite cells started testing in Oct. 2017 and are still running at room temperature, amazingly realizing 4.5 years of continuous cycling.

In an earlier interview with the Nickel Institute, Dahn said; “Our goal is to help lower the cost, increase the energy density and improve the lifetime of Li-ion cells”. Well, that goal has certainly been achieved! These single crystal LiNi_0.5Mn_0.3Co_0.2O₂ (NMC532)/graphite cells started testing in October 2017 and are still running at room temperature, amazingly realizing 4.5 years of continuous cycling with only ~ 5% degradation at 1C:1C. These incredible results can also be achieved at a higher temperature of 40 °C with 4.8 years of continuous cycling.The factors contributing to the cells' long lifetime include switching from polycrystalline NMC to single crystal NMC, the choice of quality artificial graphite (AG), and appropriate electrolyte additives.

Dahn and team also demonstrated the impact of upper cutoff voltage (UCV) in their 2022 JES publication concluding; “NMC811/graphite cells will benefit from an enormous lifetime boost when operated at a limited UCV of 4.06 V, where decades-long lifetimes can be achieved at 20 - 30 °C, if the best graphites are selected”.

Later in his IBS presentation, Dahn showed results comparison between NMC811/AG - LiPF6 vs both LFP/AG – LiPF6 and LFP/LiFSI cells at 40 °C. The NMC811 cells greatly outperformed the Dalhousie LFP cells, which according to Dahn are equivalent to the best commercial LFP cells that they know of.

The NMC811 cells greatly outperformed the Dalhousie LFP cells, which according to Dahn are equivalent to the best commercial LFP cells that they know of.

His keynote presentation was followed by a keynote panel discussion moderated by Vineet Mehta, Director of Battery Technology & Powertrain Architecture/Modeling at Tesla Motors.

_{[i] Depth of Discharge}