Co-precipitation synthesis and characterization of multiple substituted lithium manganese oxides in lithium ion batteries

Abstract

Seven electroactive compounds LiMn2O4, LiZn0.1Mn1.9O4, LiZn0.1Mn1.9O3.9F0.1, LiNi0.1Mn1.9O4, LiNi0.1Mn1.9O3.9F0.1, LiZn0.05Ni0.05Mn1.9O4 and LiZn0.05Ni0.05Mn1.9O3.9F0.1 with spinel structure, space group Fd\(\bar 3\)m, were prepared by using co-precipitation procedure carried out in water-alcohol (volume ratio 1:1) solvent using adipic acid as chelating agent. The electrochemical measurements indicated that the charge/discharge capacity of the sample prepared at 600 °C is higher than that prepared by treating at 800 °C or by microwave heating. The electrochemical properties of multi-doped samples are better than those of single and double doped samples in the Li-Mn spinel skeleton. LiZn0.05Ni0.05Mn1.9O3.9F0.1 shows the best cycle performance and the largest capacity among all prepared samples; its first discharge capacity is 96 mAh/g and the discharge capacity loses only 3.1% after 20 cycles. Cyclic voltammetry curves showed that LiZn0.05Ni0.05Mn1.9O3.9F0.1 had only one reduction-oxidation peak at 4.0 V in cyclic voltammetry measurements and could offer a more stable voltage, and also had stable electrical conductivity after 20 cycles.