Growth mechanism of Ni0.3Mn0.7CO3 precursor for high capacity Li-ion battery cathodes

Abstract

Co-precipitation is a promising method for the synthesis of precursors for lithium ion battery cathodes because it leads to homogeneous composition, narrow particle size distribution, and high packing density materials. Carbonate coprecipitation, as a process to produce transition metal (Mn, Ni, Co) precursors, [1][2][3] has many advantages compared to hydroxide process: First, in the carbonate matrix, the oxidation state of the cations is kept as 2 for all transition metals. Second, the experimental conditions under which carbonates are usually made are less harsh than those of the hydroxide process. Last but not least, carbonate is a tunable process for better morphology control.In this study, the nucleation and growth process of carbonate precursor Ni 0.3 Mn 0.7 CO 3 during coprecipitation reaction in continuous stirred tank reactor (CSTR) was investigated. Theoretical calculations were conducted to optimize pH condition in the carbonate co-precipitation reaction. It was predicted that pH zone range from 7.5 to 8.5 is the optimum pH condition for the carbonate coprecipitation.Evolution of particle size, morphology, composition and structure were characterized as a function of reaction time. It was found that the stoichiometry of the seed particles in the early stage of the reaction was richer in nickel and a small amount of Ni(OH) 2 impurity phase was observed by x-ray diffraction. The carbonate composition stabilized after several hours of co-precipitation. However, continuous growth of the precursor particles lasted for the whole synthesis process with an average particle size around 30 μm. Fig. 1 is the average particle size evolution as a function of reaction time. A linear relationship was observed between the average particle size has and the reaction time. The calculated growth rate was around 1 μm/hour, The collected precursors were washed and dried, then mixed with Li 2 CO 3 to produce the lithiated final materials Li 1.5 (Ni 0.3 Mn 0.7 )O 2+γ . The paper will discuss the relationship between the electrochemical results of the lithiated materials and the physical and morphological properties of the precursors by which those materials were prepared. The submitted manuscript has been created by UChicago Argonne, LLC, Operator of Argonne National Laboratory ("Argonne"). Argonne, a U.S. Department of Energy Office of Science laboratory, is operated under Contract No. DE-AC02-06CH11357. The U.S. Government retains for itself, and others acting on its behalf, a paid-up nonexclusive, irrevocable worldwide license in said article to reproduce, prepare derivative works, distribute copies to the public, and perform publicly and display publicly, by or on behalf of the Government.

Recent Developments in Synthesis of xLi2MnO3 · (1 − x)LiMO2 (M = Ni, Co, Mn) Cathode Powders for High-Energy Lithium Rechargeable Batteries

“…(Co 0.5 Mn 0.5 )CO 3 is prepared beforehand by mixing a solution of cobalt and manganese sulfate with ammonium bicarbonate solution. In addition, Ni x Mn 1−x CO 3 can be prepared from nickel and manganese sulfate, sodium carbonate, and ammonium hydroxide (Lee et al, 2006;Ito et al, 2008;Koenig et al, 2011;Wang et al, 2011). Another transition metal precursor is NiMnO 3 , which can be prepared by heating nickel manganese double hydroxides at 600°C for 4 h, then NiMnO 3 is mixed with lithium hydroxide for the subsequent solid-state reactions (Ohzuku et al, 2011).…”

“…Since reactions are controlled by solid-state diffusion, time, and energy consumption are important factors. For preparation of xLi 2 MnO 3 ·(1 − x)LiMO 2 (M = Ni, Co, Mn), the precursors consist of transition metal salts (acetates of Ni 2+ , Co 2+ , Mn 2+ ) (Wang et al, 2012;Yu and Zhou, 2012;Yu et al, 2012aYu et al, ,b, 2013a, manganese-nickel-cobalt hydroxides (Kim et al, 2002(Kim et al, , 2004Johnson et al, 2007;Li et al, 2011;Xu et al, 2011;, or carbonates (Deng et al, 2010;Croy et al, 2011;Koenig et al, 2011;Wang et al, 2011), and a lithium-containing compound (usually lithium hydroxide). The stoichiometric mixture is initially decomposed at 480-600°C for 3-15 h, then pelletized and calcined at 850-1000°C for 10-24 h in air.…”

Controllable Hydrothermal Conversion from Ni-Co-Mn Carbonate Nanoparticles to Microspheres

“…Many studies have shown that the electrochemical performance of the final product strongly depends on the properties of the precursor, such as morphology [10][11][12][13], size of the primary and secondary particles [13][14][15][16], size distribution [17], composition [6,8,9,[18][19][20][21], as well as structure [22,23]. Therefore, it is vital to control the precursor in order to obtain the materials with excellent performance, for which a simple and controlled preparation method is highly required.…”

“…Aiming at these problems, researchers usually use a simultaneous dripping method with a chelating agent. The dripping process is always very slow, during which controlling the synthesis condition strictly is still a difficult and tedious task [4,17,37]. The hydrothermal method could also prepare NiCoMn precursors at micron size, but it is difficult to control the morphology of particles and the starting materials are relatively expensive [38,39].…”

Understanding the Role of Solution Equilibrium and Precipitation Rate on Precursor Composition for Lithium-ion Battery Active Materials

“…While this study suggests that predictive calculations should be done to adjust the feed stoichiometry to target the desired precipitate stoichiometry, this is rarely reported. Of the 150 co-precipitation papers cited from the recent literature above, only 6 performed equilibrium calculations as part of their analysis 68,[81][82][83][84][85] , none used this analysis to guide their feed conditions, only some confirmed the stoichiometry of the transition metals in the precipitate 68,71,73,74,[86][87][88][89][89][90][91][92][93][94][95] , and none considered whether the relative rate of co-precipitation was different for the different transition metals. In this paper, we will use equilibrium calculations to guide the selection of feed conditions to achieve precursors with explicit composition control and will demonstrate the importance of such control for some solution conditions and impact on the electrochemical behavior of an exemplar cathode material.…”