两步固相碳包覆法制备磷酸锰铁锂正极材料的研究

doi:10.19964/j.issn.1006-4990.2024-0607

摘要/Abstract

摘要：

为了进一步提升磷酸锰铁锂正极材料的性能，改善材料颗粒团聚，采用两步固相碳包覆的制备方法来提高材料的电化学性能。实验结果表明：两步固相碳包覆方法未改变材料的橄榄石结构，同时与传统固相法制备的材料相比两步固相碳包覆法制备的材料颗粒粒径较小且更加分散，其中LMFP/C-2材料具有较好的结晶度；在电化学方面，两步固相碳包覆法制备的3种材料LMFP/C-1、LMFP/C-2、LMFP/C-3在0.1C（1.0C=170 mA·h/g）倍率下首次放电比容量分别为147.4、151.2、142.5 mA·h/g，循环50次后容量保持率分别为94.7%、95.3%、94.3%，通过对比，LMFP/C-2材料的电化学性能表现最佳；而传统材料在0.1C倍率下首次放电比容量仅为137.6 mA·h/g，循环50次后容量保持率为93.2%。与传统材料相比LMFP/C-2材料在0.1C倍率下首次放电比容量从137.6 mA·h/g提高到151.2 mA·h/g，循环50次后容量保持率从93.2%提高到95.3%，表明两步固相碳包覆法制备的LiMn_0.8Fe_0.2PO₄/C材料具有较好的循环性能和较高的初始容量。烧结温度和烧结时间对磷酸锰铁锂晶体具有影响，较低的温度和较短的时间会导致晶体形成不完整，影响电化学性能；较高的温度和较长的时间会导致晶体过度生长，电镜下颗粒团聚明显。研究表明，第一阶段在390 ℃下烧结5 h，第二阶段在650 ℃下烧结6 h制备的正极材料电化学性能最佳。

关键词: 磷酸锰铁锂, 两步固相法, 正极, 碳包覆

Abstract:

In order to further enhance the electrochemical performance of lithium iron manganese phosphate cathode materials and alleviate particle agglomeration，a two-step solid-phase carbon coating method was employed in this study.The experimental results indicated that this preparation technique did not alter the original olivine structure of the material.Compared with the samples synthesized via the conventional solid-phase method，the materials prepared using the two-step carbon coating approach exhibited smaller particle sizes and improved dispersion.Among the three modified samples，the LMFP/C-2 material demonstrated the highest crystallinity.The electrochemical tests conducted at a rate of 0.1C（1.0C=170 mA·h/g） reveal that the initial discharge capacities of LMFP/C-1，LMFP/C-2，and LMFP/C-3 were 147.4，151.2，and 142.5 mA·h/g，respectively.After 50 charge-discharge cycles，the corresponding capacity retention rates were 94.7%，95.3%，and 94.3%.In contrast，the conventional material exhibited an initial discharge capacity of only 137.6 mA·h/g and a capacity retention rate of 93.2% after 50 cycles.These results demonstrated that the LMFP/C-2 sample prepared via the two-step solid-phase carbon coating method achieved the best electrochemical performance.Specifically，the initial discharge capacity was increased from 137.6 mA·h/g to 151.2 mA·h/g，while the capacity retention rate was improved from 93.2% to 95.3%.It indicated that the LiMn_0.8Fe_0.2PO₄/C material synthesized using this method possessesed superior cycling stability and higher initial capacity.The sintering temperature and duration significantly influenced the crystallization of lithium iron manganese phosphate.Insufficient sintering conditions would result in incomplete crystal formation，thereby deteriorating electrochemical performance.Conversely，excessive temperatures or prolonged sintering times could lead to overgrowth of crystals and increased particle agglomeration，as observed under electron microscopy.The research indicated that the cathode materials synthesized through a two-stage sintering process exhibited optimal electrochemical performance， when the first-stage sintering process was conducted at 390 ℃ for 5 h， followed by a second-stage sintering process at 650 ℃ for 6 h.

Key words: LiMn_0.8Fe_0.2PO₄, two-step solid phase method, cathode, carbon-coated

中图分类号:

TQ131.11

苗普, 罗晓强, 侯翠红, 阮浩博, 薛灵伟. 两步固相碳包覆法制备磷酸锰铁锂正极材料的研究[J]. 无机盐工业, 2025, 57(11): 36-42.

MIAO Pu, LUO Xiaoqiang, HOU Cuihong, RUAN Haobo, XUE Lingwei. Study on preparation of lithium ferric manganese phosphate cathode materials by two-step carbon coating methods[J]. Inorganic Chemicals Industry, 2025, 57(11): 36-42.

图/表 10

图1

图2

图3

图4

图5

图6

图7

图8

图9

图10

参考文献 18

[1]	PADHI A K， NANJUNDASWAMY K S， GOODENOUGH J B.Phospho-olivines as positive-electrode materials for rechargeable lithium batteries［J］.Journal of the Electrochemical Society，1997，144（4）：1188-1194.
[2]	潘晓晓，庄树新，孙雨晴，等.动力型磷酸铁锂正极材料改性的研究进展［J］.无机盐工业，2023，55（6）：18-26.
	PAN Xiaoxiao， ZHUANG Shuxin， SUN Yuqing，et al.Research progress on modification of dynamic Ferrous lithium phosphate cathode materials［J］.Inorganic Chemicals Industry，2023，55（6）：18-26.
[3]	李志军，王红英，汤伟杰，等.锂离子电池正极材料LiMnPO₄/C的固相法制备及性能研究［J］.人工晶体学报，2015，44（3）：773-778.
	LI Zhijun， WANG Hongying， TANG Weijie，et al.Study on synthesis and characterization of LiMnPO₄/C cathode materials for lithium ion batteries by solid state method［J］.Journal of Synthetic Crystals，2015，44（3）：773-778.
[4]	FU L J， LIU H， LI C，et al.Electrode materials for lithium secondary batteries prepared by sol-gel methods［J］.Progress in Materials Science，2005，50（7）：881-928.
[5]	ZHANG Ping， LIU Debo.Effect of organic carbon coating prepared by hydrothermal method on performance of lithium iron phosphate battery［J］.Alexandria Engineering Journal，2023，80：1-7.
[6]	GUO Ju， WU Fuyong.Preparation of nano-spherical iron phosphate by hydrothermal method and its application as the precursor of lithium iron phosphate［J］.Journal of Electrochemical Energy Conversion and Storage，2021，18：011014.
[7]	ZHANG Junxi， XU Mingyu， CAO Xiaowei，et al.A synthesis route for lithium iron phosphate prepared by improved coprecipitati-on［J］.Functional Materials Letters，2010，3（3）：177-180.
[8]	李晶，秦元斌，宁晓辉.改进高温固相法制备磷酸锰铁锂正极材料［J］.材料导报，2020，34（16）：16001-16005.
	LI Jing， QIN Yuanbin， NING Xiaohui.Preparation of lithium manganese iron phosphate cathode material by improved high-temperature solid-state method［J］.Materials Reports，2020，34（16）：16001-16005.
[9]	NATARAJAN S， ARAVINDAN V.Burgeoning prospects of spent lithium-ion batteries in multifarious applications［J］.Advanced Energy Materials，2018，8（33）：1802303.
[10]	张彬，张萍，向晓刚，等.不同钴含量对三元正极材料性能的影响研究［J］.无机盐工业，2021，53（11）：91-94.
	ZHANG Bin， ZHANG Ping， XIANG Xiaogang，et al.Study on effect of different cobalt content on properties of ternary cathode materials［J］.Inorganic Chemicals Industry，2021，53（11）：91-94.
[11]	吴兆国，曹骏，杨则恒.基于水热/溶剂热法制备不同形貌LiNi_0.8Co_0.1Mn_0.1O₂锂离子电池正极材料［J］.无机盐工业，2022，54（2）：72-77，105.
	WU Zhaoguo， CAO Jun， YANG Zeheng.Preparation of LiNi_0.8Co_0.1Mn_0.1O₂ cathode materials with different morphologies based on hydrothermal/solvothermal method［J］.Inorganic Chemicals Industry，2022，54（2）：72-77，105.
[12]	马镰仁，谢红艳.采用两步固相法配合表面活性剂制备LiMn_0.7Fe_0.3PO₄/C正极材料的研究［J］.无机盐工业，2024，56（11）：39-44.
	MA Lianren， XIE Hongyan.Study on preparation of LiMn_0.7Fe_0.3PO₄/C cathode materials by two-step solid-phase method with surfactant［J］.Inorganic Chemicals Industry，2024，56（11）：39-44.
[13]	杜柯，伍斌，胡国荣，等.两步固相法制备正极材料LiNi_0.8Co_0.2O₂ ［J］.电池，2011，41（5）：264-267.
	DU Ke， WU Bin， HU Guorong，et al.Synthesis of cathode material LiNi_0.8Co_0.2O₂ by two-step solid state method［J］.Battery Bimonthly，2011，41（5）：264-267.
[14]	佟健，石迪辉，曹雁冰，等.两步碳包覆工艺制备锂离子电池正极复合材料LiFePO₄/C［J］.湖南有色金属，2015，31（1）：44-50.
	TONG Jian， SHI Dihui， CAO Yanbing，et al.Synthesis of double carbon-coated LiFePO₄/C composite cathode material by two-step synthesis route［J］.Hunan Nonferrous Metals，2015，31（1）：44-50.
[15]	WI S， PARK J， LEE S，et al.Synchrotron-based X-ray absorption spectroscopy for the electronic structure of Li_x Mn_0.8Fe_0.2PO₄ mesocrystal in Li⁺ batteries［J］.Nano Energy，2017，31：495-503.
[16]	AN Liwei， LI Zhenfei， REN Xin，et al.Low-cost synthesis of LiMn_0.7Fe_0.3PO₄/C cathode materials with Fe₂O₃ and Mn₃O₄ via two-step solid-state reaction for lithium-ion battery［J］.Ionics，2019，25（7）：2997-3007.
[17]	赵炯，李专，邹凌峰，等.溶胶-凝胶法结合二步烧结制备陶瓷刚玉磨料的微结构控制及晶粒细化机理［J］.粉末冶金材料科学与工程，2022，27（3）：319-326.
	ZHAO Jiong， LI Zhuan， ZOU Lingfeng，et al.Microstructure control and grain refinement mechanism of ceramic corundum abrasives prepared by sol-gel combined with two step sintering process［J］.Materials Science and Engineering of Powder Metallurgy，2022，27（3）：319-326.
[18]	冷科，李统业，喻冲，等.两步烧结制备细晶核燃料的研究［J］.核动力工程，2019，40（S2）：171-176.
	LENG Ke， LI Tongye， YU Chong，et al.Study on preparation of fine-grained nuclear fuel by two-step sintering［J］.Nuclear Power Engineering，2019，40，40（S2）：171-176.

首页

全国无机盐信息中心

中国化工学会

无机酸碱盐专业委员会