Li-Ni-Co-Mn-O Compound Of The Cathode Material For Lithium-Ion Battery

Li-Ni-Co-Mn-O compound is the cathode for lithium ionic battery(LIB),which integrates the respective virtues of the LiCoO₂,LiNiO₂ and LiMnO₂.This material is hopeful candidate for LiCoO₂ because of its high initial capacity, long cyclical life,good rate capability,excellent high-low temperature characters, better safety and low cost.In this work, Li-Ni-Co-Mn-O compound has been synthesized by industrial co-precipitation and solid state reaction. Three main influences on the material were discussed, the different of the molar ratio of the Li:Me(Me=Ni+Co+Mn), sinter temperatue and sinter time. the prepared material were investigated by the XRD(cystalic parameters and the intensity ratio of the chararcteristic peaks), tape density, particle distrubution, special surface area, initial capacity, the efficiency of the first charge-discharge, cycleability.The conditional experiments on three main influences were done. The results show that the different of the molar ratio of the Li:Me (1.05 - 1.15, especially in 1.10) strongly influence on performance of the material, the material prepared at 900℃for 480-960min has better ordered hexagonal layered structure and better electrochemical character.This material,which prepared at the optimal condition, has high initial capacity of 160mAh/g, the efficiency of 1st charge-discharge of 92%, the capacity retaining of 96% after 20cycles.At last, practical quadrate cell ( type:702767, standard capacity:10Ah) wered assembled, in which our industrial Li-Ni-Co-Mn-O compound was used for cathode and graphite was used for anode. The performance of the cell was evalutaed.The results show that the cathode material has high initial capacity of 160mAh/g and 220mAh/g when the voltage cut-off of 4.3V and 4.8V respective, after about 500 cycles, the capacity retention of material is 87.9%(1C charge-discharge) and 93.2%(1C charge& 5C discharge). the discharge capacity at the 0.5C, 1C, 2C, 3C,and 4C is 97.2%, 96.8%, 97.1%, 94.6% and 89.1% of discharge capacity at 0.2C. When deposited at room temeperatur(25℃) for 30 days and high temperature(60℃)for 7 days, the high residual capacity is 9.34Ah and 8.91Ah ,resoectively. In hot ovean test, shortage and overcharge(1C/6V), the cell reveals excellent safety.In summmary, Li-Ni-Co-Mn-O compound synthesized by this study has good electrochemical performance and practice using worthies.