Mitigating Jahn–Teller Distortion in LiMn_0.4Fe_0.6PO₄ via Hafnium Doping for Enhanced High-Voltage Cycling Stability

Abstract

Lithium manganese iron phosphate (LiMn_0.4Fe_0.6PO₄, LMFP) offers a significant improvement in operating voltage and energy density compared to Li (lithium) iron phosphate (LiFePO₄, LFP), garnering considerable research attention in recent years. However, LMFP suffers from low electronic conductivity and sluggish ion diffusion kinetics, resulting in poor performance under high current densities. Furthermore, the Jahn–Teller effect associated with Mn³⁺ in LMFP leads to Mn (manganese) dissolution during electrochemical reactions, which compromises structural stability and leads to suboptimal long-term cycling stability. In this study, a simple ball milling-sintering method was employed to successfully incorporate Hf⁴⁺(Hafnium) into the transition metal sites of LMFP. The higher bond energy of Hf–O compared to Mn–O enables the construction of a stable Mn–O framework through Hf doping, thereby stabilizing the lattice structure, reducing Mn dissolution, and significantly enhancing the long-term cycling performance of the material. Furthermore, Hf⁴⁺ doping improves the redox reaction kinetics of the material, increasing both the lithium-ion diffusion rate and electronic conductivity. Among the tested materials, LMFP-3%Hf exhibited the most outstanding cycling stability (with a capacity retention rate of 89.7% after 400 cycles at 1C) and rate capability (delivering a discharge specific capacity of 70 mAh g^-1 at 10C).

Keywords

Hf-ion doping / Jahn–Teller effect / lithium-ion battery / lithium manganese iron phosphate

References

[1] C. Delmas, M. Maccario, L. Croguennec, F. Le Cras, and F. Weill, “Lithium Deintercalation in LiFePO₄ Nanoparticles via a Domino-Cascade Model,” Nature Materials 7, no. 8 (2008): 665–671.

[2] X. Xu, C. Qi, Z. Hao, et al., “The Surface Coating of Commercial LiFePO₄ by Utilizing ZIF-8 for High Electrochemical Performance Lithium Ion Battery,” Nano-Micro Letters 10, no. 1 (2017): 1.

[3] J. Park, C. Gim, C. Hwang, J. Park, Y. Jung, and J. Hwang, “High-Energy LiFePO₄ Battery With Methodically Controlled Dry Electrode Processing,” Materials Science and Engineering: R: Reports 166 (2025): 101048.

[4] N. Du, X. Lei, Q. Yu, C. Wang, and S. Luo, “Unlocking the Full Potential of LiMn_1-xFe_xPO₄: Advances in Synthesis, Modification, and Future Directions for High-Energy Cathode Materials,” Materials Today Energy 52 (2025): 101965.

[5] S. Wi, J. Park, S. Lee, et al., “Synchrotron-Based X-Ray Absorption Spectroscopy for the Electronic Structure of Li_xMn_0.8Fe_0.2PO₄ Mesocrystal in Li⁺ Batteries,” Nano Energy 31 (2017): 495–503.

[6] B. Zhang, X. Wang, S. Wang, et al., “High-Energy-Density Lithium Manganese Iron Phosphate for Lithium-Ion Batteries: Progresses, Challenges, and Prospects,” Journal of Energy Chemistry 100 (2025): 1–17.

[7] K. Zhang, Z.-X. Li, X. Li, et al., “Perspective on Cycling Stability of Lithium-Iron Manganese Phosphate for Lithium-Ion Batteries,” Rare Metals 42, no. 3 (2023): 740–750.

[8] Y. Liu, X. Wen, T. Huang, and A. Yu, “Electrochemically Induced Interface by LiBOB to Enhance Cycling Performance of LiFe_0.4Mn_0.6PO₄ Cathode for Lithium-Ion Batteries,” Journal of Power Sources 623 (2024): 235398.

[9] L. Wen, Y. Shi, L.-W. Ye, C. Wang, and F. Li, “Progress of Lithium Manganese Iron Phosphate in Blended Cathode Materials,” Materials Science and Engineering: R: Reports 164 (2025): 100952.

[10] S. Li, H. Zhang, Y. Liu, L. Wang, and X. He, “Comprehensive Understanding of Structure Transition in LiMn_yFe_1-yPO₄ During Delithiation/Lithiation,” Advanced Functional Materials 34, no. 4 (2024): 2310057.

[11] R. Yang, L. Chang, S. Luo, et al., “A Critical Revelation of Lithium Ferromanganese Phosphate (LMFP) Performance in a Mn-Rich Cathode for Li-Ion Batteries Using Fe Equivalents to Occupy a Mn Site,” Journal of Materials Chemistry C 12, no. 14 (2024): 4961–4976.

[12] Q. Hu, L. Wang, G. Han, et al., “Revealing the Voltage Decay of LiMn_0.7Fe_0.3PO₄ Cathodes Over Cycling,” Nano Energy 123 (2024): 109422.

[13] S. Tian, K. Zhang, J. Cao, H. Guo, R. Liu, and G. Liang, “Spherical Ni-Doped LiMn_0.6Fe_0.4PO₄/C Composites With High-Rate Performance,” Ionics 27, no. 7 (2021): 2877–2887.

[14] H. Yi, C. Hu, H. Fang, et al., “Optimized Electrochemical Performance of LiMn_0.9Fe_0.1-xMg_xPO₄/C for Lithium Ion Batteries,” Electrochimica Acta 56, no. No.11 (2011): 4052–4057.

[15] X. Gao, S. Zheng, Y. Song, et al., “Ti Doping and Fe-Vacancy Synergistically Enhance Rate Capacity of Lithium Manganese Iron Phosphate,” Journal of Energy Storage 131 (2025): 117670.

[16] B. Zhang, S. Wang, L. Liu, H. Liu, and J. Yang, “Enhancement of Li₂ZrO₃ Modification of the Cycle Life of N/S-Doped LiMn_0.5Fe_0.5PO₄/C Composite Cathodes for Lithium Ion Batteries,” Langmuir 39, no. 14 (2023): 5187–5198.

[17] Z. Peng, X. Xia, Y. Xiao, and T. Huang, “Progress on Lithium Manganese Iron Phosphate Cathode Materials,” Journal of Alloys and Compounds 1016 (2025): 178901.

[18] B. Hu, J. Jiang, L. Luo, et al., “Bimetallic Ions-Doped LiMn_0.6Fe_0.4PO₄/C via Carbothermal Reduction to Enhance Manganese Reaction Kinetics,” Journal of Power Sources 658 (2025): 238216.

[19] J. Tu, K. Wu, H. Tang, H. Zhou, and S. Jiao, “Mg-Ti Co-Doping Behavior of Porous LiFePO₄ Microspheres for High-Rate Lithium-Ion Batteries,” Journal of Materials Chemistry A 5, no. 32 (2017): 17021–17028.

[20] H. Li, Y. Luo, S. Z. Yang, et al., “Synergistic Intermolecular Hydrogen-Bonded Cross-Linking and Steric Hindrance Effects Enabling Pomegranate-Type LMFP@C for Li⁺ Storage,” Rare Metals 44, no. 1 (2025): 147–157.

[21] T. F. Yi, Y. Li, Z. Fang, P. Cui, S. Luo, and Y. Xie, “Improving the Cycling Stability and Rate Capability of LiMn_0.5Fe_0.5PO₄/C Nanorod as Cathode Materials by LiAlO₂ Modification,” Journal of Materiomics 6, no. 1 (2020): 33–44.

[22] L. Wang, Y. Li, J. Wu, et al., “Synthesis Mechanism and Characterization of LiMn_0.5Fe_0.5PO₄/C Composite Cathode Material for Lithium-Ion Batteries,” Journal of Alloys and Compounds 839 (2020): 155653.

[23] P. Yang, D. Gao, Y. Yang, et al., “Enhancing d-p Orbital Coupling by Hf Doping to Construct a Stable LiMn₂O₄ Cathode for Lithium-Ion Batteries,” Nano Energy 125 (2024): 109570.

[24] Z. Li, Y. You, Z. Zhu, et al., “The Synergistic Enhancement of Electrochemical Performance in LiMn_0.5Fe_0.5PO₄ Through V Doping and V₂CT_x MXene Coating,” Journal of Energy Storage 110 (2025): 115111.

[25] S. B. Kim, H. Kim, D. H. Park, et al., “Li-Ion Diffusivity and Electrochemical Performance of Ni-Rich Cathode Material Doped With Fluoride Ions,” Journal of Power Sources 506 (2021): 230219.

[26] J. Zhang, X. Zhao, Y. Song, et al., “Understanding the Superior Sodium-Ion Storage in a Novel Na_3.5Mn_0.5V_1.5(PO₄)₃ Cathode,” Energy Storage Materials 23 (2019): 25–34.

[27] H. Zhang, Z. Wei, J. Jiang, et al., “Three Dimensional Nano-LiMn_0.6Fe_0.4PO₄@C/CNT as Cathode Materials for High-Rate Lithium-Ion Batteries,” Journal of Energy Chemistry 27, no. 2 (2018): 544–551.

[28] Z. Lin, Y. Ying, Z. Xu, et al., “A Multifunctional Zeolite Film Enables Stable High-Voltage Operation of a LiCoO₂ Cathode,” Energy & Environmental Science 18, no. 1 (2025): 334–346.

[29] J. Liu, Y. Wang, N. Jiang, B. Wen, C. Yang, and Y. Liu, “Vacancies-Regulated Prussian Blue Analogues Through Precipitation Conversion for Cathodes in Sodium-Ion Batteries With Energy Densities Over 500 Wh/kg,” Angewandte Chemie International Edition 63, no. 39 (2024): e202400214.

[30] Q. Hu, J. Liao, X. Xiao, et al., “Ultrahigh Rate Capability of Manganese Based Olivine Cathodes Enabled by Interfacial Electron Transport Enhancement,” Nano Energy 104 (2022): 107895.

[31] Z. Lin, Z. Xu, Y. Ying, G. Chen, et al., “Nano-Particulate Surface Pinning of CeO₂ Enables Durable High-Voltage Lithium-Ion Batteries,” Advanced Materials 38, no. 3 (2026): e17074.

[32] D. B. Ravnsbæk, K. Xiang, W. Xing, et al., “Engineering the Transformation Strain in LiMn_yFe_1-yPO₄ Olivines for Ultrahigh Rate Battery Cathodes,” Nano Letters 16, no. 4 (2016): 2375–2380.

[33] N. Meethong, H. Y. S. Huang, S. A. Speakman, W. Carter, and Y. Chiang, “Strain Accommodation During Phase Transformations in Olivine-Based Cathodes as a Materials Selection Criterion for High-Power Rechargeable Batteries,” Advanced Functional Materials 17, no. 7 (2007): 1115–1123.

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2026 The Author(s). Carbon Neutralization published by Wenzhou University and John Wiley & Sons Australia, Ltd.