4.7 V Li-ion cells: Nonsense or Possibility

摘要

1. It is important to recognize the issues associated with charging NMC-based cells to high voltage, virtually all of which stem from electrolyte oxidation (in our opinion). 2. Some progress has been made in our lab with electrolyte additives in conventional solvents to enable decent cycling to 4.4 V and 4.5 V at 40 and 45°C. These stabilize the positive electrode/electrolyte interface and prevent rampant impedance growth. 3. The Pyridine:BF_3 additives developed by Mengyun Nie are looking very promising at this time. Contact Kevin Eberman at 3M to learn more and obtain samples. 4. Changing to other solvents may be essential to go to even higher voltages.