Ammonolysed LiNi $$_{0.8}\hbox {Co}_{0.15}\hbox {Al}_{0.05}\hbox {O}_{2}$$ 0.8 Co 0.15

Abstract

In this work, ammonolysed LiNi 0.8 Co 0.15 Al 0.05 O 2 (NCA) prepared by co-precipitation and subsequent ammonolysis was investigated as a cathode material for Li-ion batteries with enhanced rate capability. Detailed structural and morphological property characterization demonstrated that ammonolysis results in the incorporation of a small amount of nitrogen into the surface layer of the afore-mentioned material. The electrochemical performances of NCA electrodes were measured by galvanostatic charging-discharging of the corresponding Li-ion cells, revealing that ammonolysed NCA exhibited higher capacity and rate capability than those of the pristine sample, i.e., after 20 cycles, the discharge capacity of the former equalled 176 mA h g −1 at a current density of 18.4 mA g −1 , remaining as high as 107 mA h g −1 at a high current density of 1840 mA g −1. This improved performance was ascribed to ammonolysis-induced surface changes, which reduced cell polarization during cycling and enhanced the electrochemical stability and reaction kinetics of NCA electrodes.