Leinonen Jere, Laine Petteri, Hu Tao, Kankaanpää Timo, Kervinen Immo, Tynjälä Pekka, Lassi Ulla
University of Oulu, Research Unit of Sustainable Chemistry, Faculty of Technology, Oulu 90014, Finland.
Kokkola University Consortium Chydenius, University of Jyvaskyla, Applied Chemistry Unit, Kokkola 67100, Finland.
ACS Omega. 2025 Aug 14;10(33):37128-37140. doi: 10.1021/acsomega.5c01869. eCollection 2025 Aug 26.
Layered transition metal oxides are an attractive material for Na-ion batteries because of the possibility of using abundant and inexpensive materials such as Fe, Mn, and NaCO. However, scientific literature on the effect of coprecipitation parameters on Fe-containing cathode precursor materials is lacking. Herein, the effect of pH, temperature, and stirring rate on particle size distribution, tap density, surface area, and morphology of FeMnCO precursors is studied. Higher coprecipitation temperature favors the formation of larger precursor particles. The highest tap densities between 1.8 and 1.9 g/cm were achieved at 60 °C. Particles with a usually preferred D50 of ≈10 μm were achieved when the precipitation temperature was around 40-50 °C. The particle size grew when the pH was increased, except at pH 8, where the smallest particles were achieved. The coprecipitation was not homogeneous, as the core of the particles was less dense than the outer layer of the particle and had a higher Fe concentration and a lower Mn and O concentration than the outer layer. High temperature and pH favored the formation of cubic or rhombohedral primary particles on the surface of the spherical particles. An even higher stirring rate (>1200 rpm) than what is possible with our experimental setup is preferred to prevent agglomeration. Further research should be done on the coprecipitation of Fe Mn CO precursors.
层状过渡金属氧化物是钠离子电池的一种有吸引力的材料，因为有可能使用铁、锰和碳酸钠等丰富且廉价的材料。然而，关于共沉淀参数对含铁阴极前驱体材料影响的科学文献却很缺乏。在此，研究了pH值、温度和搅拌速率对FeMnCO前驱体的粒度分布、振实密度、表面积和形态的影响。较高的共沉淀温度有利于形成更大的前驱体颗粒。在60°C时达到了1.8至1.9 g/cm之间的最高振实密度。当沉淀温度在40-50°C左右时，通常可获得D50约为10μm的优选颗粒。除了在pH值为8时获得最小颗粒外，随着pH值的增加颗粒尺寸会增大。共沉淀不均匀，因为颗粒的核心比颗粒外层密度小，且铁浓度比外层高，锰和氧浓度比外层低。高温和pH值有利于在球形颗粒表面形成立方或菱面体初级颗粒。为防止团聚，优选比我们实验装置所能达到的更高的搅拌速率（>1200 rpm）。应进一步研究FeMnCO前驱体的共沉淀。
