Chemical Industry and Engineering Progress ›› 2024, Vol. 43 ›› Issue (1): 302-309.DOI: 10.16085/j.issn.1000-6613.2023-1224

• Column: Chemical process intensification • Previous Articles    

Synthesis and modification of F-doped olivine LiFe0.5Mn0.5PO4 cathode materials for Li-ion batteries

YU Songmin1(), JIN Hongbo2, YANG Minghu3, YU Haifeng2, JIANG Hao1,2()   

  1. 1.Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China
    2.Shanghai Engineering Research Center of Multistage Structural Nanomaterials, College of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
    3.AnHui Polymeric Chemicals Co. , Ltd. , Chuzhou 233200, Anhui, China
  • Received:2023-07-18 Revised:2023-08-13 Online:2024-02-05 Published:2024-01-20
  • Contact: JIANG Hao

氟掺杂改性LiMn0.5Fe0.5PO4正极材料及其电化学性能

于松民1(), 金洪波2, 杨明虎3, 余海峰2, 江浩1,2()   

  1. 1.华东理工大学材料科学与工程学院超细材料制备与应用教育部重点实验室,上海 200237
    2.华东理工大学化工学院上海多级结构纳米材料工程技术研究中心,上海 200237
    3.安徽聚合辐化化工有限公司,安徽 滁州 233200
  • 通讯作者: 江浩
  • 作者简介:于松民(1998—),男,硕士研究生,研究方向为磷酸锰铁锂材料制备与改性。E-mail:742703361@qq.com
  • 基金资助:
    国家自然科学基金(21975074)

Abstract:

At present, LiFePO4 materials is difficult to meet the demand of high energy density. LiMn x Fe1-x PO4 (LMFP) cathode materials exhibit higher energy density compared with LiFePO4, while maintain the advantage of low cost and high stability of olivine structure. However, the inferior rate and cycle performance limit its practical application, which is ascribed by poor Li-ion diffusion kinetic and Jahn-Teller effect of Mn3+. In this work, a F-doping strategy was proposed to construct 110nm nanoparticles of LMFP with highly ordered b-axis orientation. The basic physicochemical properties and electrochemical properties of materials were explored, finding that the exposed (010) crystal face acted as Li-ion diffusion channel can significantly improve the Li-ion transport efficiency, while the doped F ions can increase the Li—O bond distance and the PO43- binding energy to enhance the stability of crystal structure. Therefore, the reversible specific discharge capacity of the F-doped LMFP was 153mA·h/g and 106mA·h/g at 0.1C and 5C, respectively. After 750 cycles at 1C, the capacity retention increased from 90.6% to 96.4% compared with the unmodified material.

Key words: electrochemistry, lithium iron manganese phosphate (LiMn0.5Fe0.5PO4), cathode, lithium-ion battery, F-doping

摘要:

目前磷酸铁锂材料由于其较低的能量密度难以满足使用需求。磷酸锰铁锂具有比磷酸铁锂更高的能量密度,同时兼顾磷酸铁锂低成本和晶体结构稳定性的特点。然而缓慢的锂离子扩散动力学和Mn3+引起的Jahn-Teller效应导致材料的循环和倍率性能差,限制了磷酸锰铁锂实际应用。本工作通过引入F离子掺杂,构筑沿b轴取向生长的110nm纳米颗粒磷酸锰铁锂正极材料,探究了它们的基本物理化学性质与电化学性能,发现沿b轴取向生长并暴露的(010)晶面能够显著提升锂离子扩散动力学。此外,F离子引入显著增强了Li—O键以及PO43-骨架结构,提高锂离子嵌入和脱出过程中晶体结构稳定性。因此,在0.1C和5C电流下,改性磷酸锰铁理正极材料可逆放电比容量分别为153mA·h/g和106mA·h/g。相比于未改性材料,1C循环750次后比容量保持率从90.6%提升到96.4%。

关键词: 电化学, 磷酸锰铁锂, 正极, 锂离子电池, 氟掺杂

CLC Number: 

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