A modified Al2O3 coating process to enhance the electrochemical performance of Li(Ni1/3Co1/3Mn1/3)O2 and its comparison with traditional Al2O3 coating process

Abstract Al 2 O 3 -modified Li(Ni 1/3 Co 1/3 Mn 1/3 )O 2 is synthesized by a modified Al 2 O 3 coating process. The Al 2 O 3 coating is carried out on an intermediate, (Ni 1/3 Co 1/3 Mn 1/3 )(OH) 2 , rather than on Li(Ni 1/3 Co 1/3 Mn 1/3 )O 2 . As a comparison, Al 2 O 3 -coated Li(Ni 1/3 Co 1/3 Mn 1/3 )O 2 also is prepared by traditional Al 2 O 3 coating process. The effects of Al 2 O 3 coating and Al 2 O 3 modification on structure and electrochemical performance are investigated and compared. Electrochemical tests indicate that cycle performance and rate capability of Li(Ni 1/3 Co 1/3 Mn 1/3 )O 2 are enhanced by Al 2 O 3 modification without capacity loss. Al 2 O 3 coating can also enhance the cycle performance but cause evident capacity loss and decline of rate capability. The effect of Al 2 O 3 coating and Al 2 O 3 modification on kinetics of lithium-ion transfer reaction at the interface of electrode/electrolyte is investigated via electrochemical impedance spectra (EIS). The result support that the Al 2 O 3 modification increase Li + diffused coefficient and decrease the activation energy of Li + transfer reaction but the traditional Al 2 O 3 coating lead to depression of Li + diffused coefficient and increase of activation energy.