The 3-phenyl-1,4,2-dioxazol-5-one (PDO) Electrolyte Additive for Li(Ni0.6Mn0.2Co0.2)O2 and Li(Ni0.8Mn0.1Co0.1)O2 Lithium-Ion Cells

Electrolyte additives, as a small proportion of the electrolyte, greatly affect the performance of lithium-ion cells. This work performs a comparative study to reveal the difference between commercial 99.8% pure 3-phenyl-1,4,2-dioxazol-5-one (PDO) additive and lab-made 95% pure PDO in NMC622/graphite cells. In addition, a set of experiments were conducted to evaluate the performance of 99.8% pure PDO and its binary blends with vinylene carbonate (VC), 1,3,2-dioxathiolane-2,2-dioxide (DTD) or lithium difluorophosphate (LFO) in NMC811/graphite cells. 99.8% Pure PDO and 95% pure PDO show little difference in the NMC622 cells, with the latter presenting relatively better performance in the best-performing blends for long-term cycling and high-temperature storage tests. Considering all the tests including ultra high precision coulometry (UHPC) cycling, long-term cycling, and high-temperature storage, the NMC811 cells with 2%PDO+ 1%LFO outperformed the other PDO-containing cells. The PDO-based blends were confirmed to be more promising in cells with higher nickel content; that is, PDO could be a useful additive in high-nickel content cells.

Automated summary

Electrolyte additives significantly affect the performance of lithium-ion cells. In comparative studies, lab-made 95% pure PDO outperformed commercial 99.8% pure PDO in certain tests. Among the PDO-containing cells, the blend of 2%PDO+ 1%LFO showed the best performance in NMC811 cells. PDO-based blends are more promising in cells with higher nickel content.