Study on the Optimum Conditions for Synthesizing a Cathode Active Material Precursor in Li-Ion Batteries Using a Taylor Reactor

摘要

Li(Ni_(1-x-y)Co_xMn_y)O_2 (NCM) materials, which are the cathode active material for lithium ion batteries, have been developed and widely used as an alternative to lithium cobalt oxide, because of the high cost of cobalt. To synthesize high quality NCM materials, it is important to control the process manufacturing of the NCM precursor. We synthesized a precursor for LiNi_(0.6)Co_(0.2)Mn_(0.2)O_2 with high capacity through the co-precipitation method using the Taylor reactor. First, it was confirmed that the optimum concentration of ammonia water, which is complexing agent, was 2 M, for uniform particle contribution. The average particle size distributions of the synthesized NCM precursors, and the analysis of the crystal phase and the composition of the NCM precursor, were investigated using a Taylor reactor which is capable of a continuous production process. A reference sample fabricated at a stirring rate of 1,000 rpm showed a composition similar to the target NCM material. When the reaction time was more than 24 hours, the concentration in the Taylor reactor reached a constant steady state, and it was confirmed that continuous production is possible after a reaction time of 24 hours. The use of Taylor reactors can be an effective process because the NCM precursor can be continuously produced, and it is possible to reduce agitation time.