焦磷酸亚锰铁固溶体连续化生产装置设计

doi:10.19799/j.cnki.2095-4239.2025.0493

摘要/Abstract

摘要：

锂离子电池正极材料磷酸锰铁锂（LiFe_1-yMn_yPO₄，记作LMFP）因两相（LiFePO₄与LiMnPO₄）堆叠、锰铁分布不均及电化学性能退化等问题，严重阻碍其商业化应用。本研究提出基于焦磷酸亚锰铁（(Fe_1-yMn_y)₂P₂O₇，MFP）固溶体的前驱体均匀化策略，通过开发和设计雾化高温合成（AHTS）炉，实现MFP的连续化生产，进而制备高性能LMFP正极材料。MFP前驱体以原子级Fe/Mn共沉淀为核心，将均匀性传递至LMFP晶格，抑制反位缺陷并消除两相堆叠共存，突破传统改性方法（如碳包覆、掺杂等）的局限。AHTS-MFP工艺采用微米级雾状液滴反应器，结合多约束耦合迭代优化设计方法，开发专用合成装置。通过三维热力学-流体力学-化学反应动力学多场耦合仿真，优化流场、温度场及氧浓度控制，形成稳定气旋锁结构，确保雾状液滴在炉膛内依次经历蒸发、共沉淀、干燥与缩合反应，停留时间大于15秒，实现材料的高结晶度与元素均质性。装置关键设计涵盖对称喷嘴阵列、切向火道燃烧系统及多层阻氧复合结构，结合动态氮气注入技术，将炉内氧浓度精准控制在小于1%。生产试验所制(Fe_0.35Mn_0.65)₂P₂O₇样品的SEM图像、XRD图谱、HAADF-STEM图像与EDS映射图显示样品为各元素分布均匀的固溶体材料。由其制备的LMFP正极材料LiFe_0.35Mn_0.65PO₄呈均一橄榄石型结构，XRD无杂相，HAADF-STEM图像与EDS映射图显示样品各元素分布均匀，证实前驱体的均匀性成功传递至终产物。本研究通过工艺与装备创新，攻克LMFP工业化中两相堆叠与元素分布不均的难题，为其工业化生产提供了关键技术支撑。

关键词: 焦磷酸亚锰铁, 磷酸锰铁锂, 雾化高温合成, 固溶体

Abstract:

The commercialization of lithium manganese iron phosphate (LiFe_1-yMn_yPO₄, LMFP) as a cathode material for lithium-ion batteries has been severely hindered by challenges such as two-phase stacking (LiFePO₄ & LiMnPO₄), inhomogeneous Mn/Fe distribution, and electrochemical performance degradation. This study proposes a precursor homogenization strategy based on manganese iron pyrophosphate ((Fe_1-yMn_y)₂P₂O₇, MFP) solid solutions. By developing and designing an atomization high-temperature synthesis (AHTS) roaster, continuous production of MFP was achieved, enabling the preparation of high-performance LMFP cathode materials. The MFP precursor employs atomic-scale Fe/Mn co-precipitation to transfer uniformity to the LMFP lattice, suppressing anti-site defects and eliminating two-phase stacking coexistence, thereby overcoming the limitations of traditional modification methods (e.g., carbon coating, doping). The AHTS-MFP process utilizes a micron-scale atomized droplet reactor and a multi-constraint coupled iterative optimization design method to develop a specialized synthesis device. Through three-dimensional coupled thermodynamics-fluid dynamics-chemical reaction kinetics simulations, flow field, temperature field, and oxygen concentration control were optimized, forming a stable "gas vortex lock" structure. This ensures that atomized droplets undergo evaporation, co-precipitation, drying, and condensation reactions sequentially within the furnace, with a residence time exceeding 15 seconds, achieving high crystallinity and elemental homogeneity. Key designs include symmetrical nozzle arrays, a tangential flue combustion system, and a multi-layer oxygen-blocking composite structure, combined with dynamic nitrogen injection technology to precisely control the oxygen concentration in the roaster below 1%. The SEM images, XRD patterns, HAADF-STEM images, and EDS mapping results of the samples (Fe_0.35Mn_0.65)₂P₂O₇ prepared in the production test show that the samples are solid solution materials with uniform distribution of each element. The LMFP cathode material LiFe_0.35Mn_0.65PO₄ prepared from it exhibits a uniform olivine-type structure. The XRD pattern shows no secondary phases, and the HAADF-STEM images and EDS mapping results indicate that each element in the sample is uniformly distributed, confirming that the uniformity of the precursor is successfully transmitted to the final product. Through process and equipment innovation, this study has overcome the problems of two-phase stacking and uneven element distribution in LMFP industrialization, providing key technical support for its industrial production.

Key words: Manganese iron pyrophosphate (MFP), Lithium manganese iron phosphate (LMFP), Atomization high-temperature synthesis (AHTS), Solid solution

中图分类号:

TK02

汤凯. 焦磷酸亚锰铁固溶体连续化生产装置设计[J]. 储能科学与技术, doi: 10.19799/j.cnki.2095-4239.2025.0493.

Kai TANG. Design of a Continuous Production Facility for Solid-Solution Manganese Iron Pyrophosphate[J]. Energy Storage Science and Technology, doi: 10.19799/j.cnki.2095-4239.2025.0493.

图/表 10

图1

表1

图2

表2

模型常数"

参数	近壁区（F₁=1）	自由剪切流（F₁=0）
$σ k$	0.85	1.0
$σ ω$	0.5	0.856
$β$	0.075	0.0828
$α$	5/9	0.44

表2

图3

图4

图5

图6

图7

图8

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约束条件	关键参数	设计依据
1	固溶体，无杂相	产品目标要求
2	反应时长>15 s	雾化高温合成炉制备焦磷酸亚锰铁的工作原理
3	氧气浓度<1%	防止Fe²⁺、Mn²⁺离子被氧化
4 4 4 4	喷嘴附近300~450 ℃ 喷嘴往下400~500 ℃ 炉膛中部500~750 ℃ 炉壁附近750~850 ℃	雾化高温合成炉制备焦磷酸亚锰铁的工作原理雾化高温合成炉制备焦磷酸亚锰铁的工作原理雾化高温合成炉制备焦磷酸亚锰铁的工作原理雾化高温合成炉制备焦磷酸亚锰铁的工作原理