Corrosion inhibition of aluminum current collector with molybdate conversion coating in commercial LiPF₆-esters electrolytes

A molybdate conversion coating (MCC) is developed to circumvent aluminum current collector (AlCC) corrosion in commercial LiPF₆-esters electrolytes. The obtained MCC exhibits compact structure and good combination with AlCC matrix. Electrochemical tests show that MCC reduces the corrosion current density by an order of magnitude. Furthermore, in Li||NMC333 cells, the capacity retention of the cell with MCC-AlCC cathode is 75.6 % at 4.5 V high voltage, while that of control cell is only 7.2 %. The anticorrosion mechanism could be contributed to the stable artificial passivation layer which prevents HF erosion and the depth expansion of pitting corrosion.