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

LiNi 1 − y Ti y O 2 (0.000 ≤ y ≤ 0.100) and LiNi 0.990 M 0.010O2 (M = Zn, Al, and Ti) were synthesized by the combustion method. The effects of Zn, Al and Ti substitution for Ni of LiNiO 2 on the electrochemical properties of LiNiO 2 were investigated. LiNi 0.995 Ti 0.005 O 2 has the largest first discharge capacity (188.1 mA h/g) among the Ti-substituted samples. LiNi 0.990 Ti 0.010 O 2 has a relatively large first discharge capacity (185.5 mA h/g) and a relatively good cycling performance. Among LiNi 0.990 M 0.010 O 2 (M = Ni, Zn, Al, and Ti), LiNiO 2 has the largest discharge capacities at a rate of 0.1 C from n = 1(189.3 mA h/g) to n = 10. LiNi 0.990 Al 0.010 O 2 has the lowest discharge capacities from n = 1 to n = 10, but it has the best cycling performance. LiNi 0.99 0Zn 0.010 O 2 showed poor crystallinity, LiNi 0.990 Ti 0.010 O 2 showed high cation mixing, and LiNi 0.990 Al 0.010 O 2 had good crystallinity and showed low cation mixing. Fewer occurrence of phase transitions and the least change of the −d x /|d V | vs. voltage curve at the second cycle from the curve at the first cycle of LiNi 0.990 Al 0.010 O 2 suggest that Al substitution stabilizes the structure and leads to a good cycling performance.