Effects of Zn, Al and Ti substitution on the electrochemical properties of LiNiO2 synthesized by the combustion method

Abstract

LiNi1 − yTiyO2 (0.000 ≤ y ≤ 0.100) and LiNi0.990M0.010O2 (M = Zn, Al, and Ti) were synthesized by the combustion method. The effects of Zn, Al and Ti substitution for Ni of LiNiO2 on the electrochemical properties of LiNiO2 were investigated. LiNi0.995Ti0.005O2 has the largest first discharge capacity (188.1 mA h/g) among the Ti-substituted samples. LiNi0.990Ti0.010O2 has a relatively large first discharge capacity (185.5 mA h/g) and a relatively good cycling performance. Among LiNi0.990M0.010O2 (M = Ni, Zn, Al, and Ti), LiNiO2 has the largest discharge capacities at a rate of 0.1 C from n = 1(189.3 mA h/g) to n = 10. LiNi0.990Al0.010O2 has the lowest discharge capacities from n = 1 to n = 10, but it has the best cycling performance. LiNi0.990Zn0.010O2 showed poor crystallinity, LiNi0.990Ti0.010O2 showed high cation mixing, and LiNi0.990Al0.010O2 had good crystallinity and showed low cation mixing. Fewer occurrence of phase transitions and the least change of the −dx/|dV| vs. voltage curve at the second cycle from the curve at the first cycle of LiNi0.990Al0.010O2 suggest that Al substitution stabilizes the structure and leads to a good cycling performance.