Precursor Morphology Control and Electrochemical Properties of LiNi_0.35Mn_0.30Co_0.35O₂ as a Li-Ion Battery Positive Electrode Material

Abstract

To control the electrochemical properties of LiNi 0.35 Mn 0.30 Co 0.35 O 2 (NMC) acting as a positive electrode material, Ni 0.35 Mn 0.30 Co 0.35 (OH) 2 precursors with different morphologies were synthesized by controlling the dissolved oxygen concentration during coprecipitation. As the dissolved oxygen concentration increases, precursor particles become more porous and have higher specific surface area. X-ray absorption spectroscopy clearly shows that only the Mn valence in the precursors increased with increasing dissolved oxygen concentration. X-ray diffraction patterns of the precursor synthesized under a high dissolved oxygen concentration suggested the formation of oxyhidroxide. The morphology of NMC synthesized using the developed precursors resembled that of the precursors. NMC with dense morphology exhibited high volumetric energy density, while that with porous morphology exhibited a high discharge capacity and rate performance without any cycle performance drawbacks. We expect that this simple method of morphology control by control of precursor dissolved oxygen concentration can be applied to improve the electrochemical properties of positive electrode materials with a wide range of Mn-containing compositions.

Method for predicting the size of Ni1/3Mn1/3Co1/3(OH)2 particles precipitated in a stirred-tank semi-batch crystallizer using CFD and particle agglomeration models

“…At this stage, no further agglomeration between particles is observed, and the rounded particles are uniform in size. A similar particle growth process was also observed during the reaction crystallization of Ni 0.35 Mn 0.30 Co 0.35 (OH) 2 studied by Koshika et al [ 2 ].…”

“…Ni x Mn y Co z (OH) 2 is widely used as a precursor for LiNi x Mn y Co z O 2 , the cathode active material in lithium-ion batteries [ [1] , [2] , [3] , [4] , [5] ], and its battery characteristics are substantially affected by the morphology (e.g., internal surface area, porosity, and structure) of the cathode active material [ 1 , 3 ]. Because the morphology is determined by the powder characteristics of the precursor (size distribution, porosity, and apparent density), quantitative understanding of the effects of the scale of the equipment used to synthesize the precursor and the conditions of the reaction operation on the powder characteristics is essential for manufacturing the precursor.…”

“…Most of Ni x Mn y Co z (OH) 2 used as a precursor for cathode active materials is produced by precipitation reaction in a stirred-tank crystallizer for homogeneous mixing. Therefore, numerous experimental studies have been conducted for the precipitation of Ni x Mn y Co z (OH) 2 in stirred tank-type reaction crystallizers [ 2 , [6] , [7] , [8] , [9] ], where Ni x Mn y Co z (OH) 2 was precipitated under controlled temperature, pH, ammonia concentration in the bulk liquid, and impeller speed conditions to investigate the effect of these conditions on powder characteristics such as precursor size and apparent density. However, it is unclear how the scale of the reaction crystallizer and the turbulent mixing rate affects the particle growth mechanism of Ni x Mn y Co z (OH) 2 .…”

“…The flow field, mixing state, and supersaturation distribution of the equipment were analyzed by CFD, and the effects of the operating conditions, such as the flow rate and inlet concentration, on the crystallite size were quantified. Although the residence time in this reactor is less than 1 s, some studies that observed the particle growth of Ni x Mn y Co z (OH) 2 in a stirred-tank reaction crystallizer [ 2 , 9 ] suggested that the particle growth mechanism changes over several tens of minutes after the reaction operation begins. Moreover, because the study was focused on the subject of multi-inlet vortex mixers, the effect of reactor scale-up on particle growth was not discussed.…”

Degradation mechanisms and modification strategies of nickel-rich NCM cathode in lithium-ion batteries

“…The effective management of Li/Ni disorder can be achieved through the identification of the optimal sintering temperature or by adjusting the precursor type [39,40] and lithium salt ratio [41,42]. Ronduda et al [43] delved into the impact of calcination temperature on cathode materials, specifically LiNi 0.6 Mn 0.2 Co 0.2 O 2 (NCM622).…”