Fluorinated Rocksalt-Polyanion Cathode for Lithium-Ion Batteries

Abstract

Integrated rocksalt-polyanion cathodes (DRXPS) are promising candidates for next-generation lithium-ion battery cathode materials that combine high energy density, stable cycling performance, and reduced reliance on Co and Ni. In this work, we investigated Li₃Mn_1.6P_0.4O_5.4F_0.6, a new DRXPS cathode with fluoride incorporation. A pure spinel phase was formed and a discharge capacity retention of 84% was achieved after 200 cycles between 1.5 and 4.8 V versus Li/Li⁺. In comparison, the similarly synthesized Li₃Mn_1.6Nb_0.4O_5.4F_0.6, in which all P⁵⁺ was substituted by Nb⁵⁺ while maintaining the same stoichiometry for all other elements, crystallized in a disordered rocksalt structure, and exhibited inferior capacity retention and rate capability than the P⁵⁺ counterpart. Our findings expand the compositional space of DRXPS to include F⁻, justify the viability of integrating polyanion groups in rocksalt-type cathodes, and highlight the superiority of P⁵⁺ as a cation charge compensator compared to the commonly used Nb⁵⁺. This work thereby advances the design of robust, high-performance cathode materials for sustainable batteries.

References

[1] J. B. Goodenough and K. S. Park, “The Li-ion Rechargeable Battery: A Perspective,” Journal of the American Chemical Society135, no. 4 (2013): 1167-1176.

[2] S. Ahmed, P. A. Nelson, K. G. Gallagher, N. Susarla, and D. W. Dees, “Cost and Energy Demand of Producing Nickel Manganese Cobalt Cathode Material for Lithium-ion Batteries,” Journal of Power Sources342 (2017): 733-740.

[3] J. Lee, A. Urban, X. Li, D. Su, G. Hautier, and G. Ceder, “Unlocking the Potential of Cation-Disordered Oxides for Rechargeable Lithium Batteries,” Science343, no. 6170 (2014): 519-522.

[4] J. Lee, D. A. Kitchaev, D. H. Kwon, et al., “Reversible Mn²⁺/Mn⁴⁺ Double Redox in Lithium-Excess Cathode Materials,” Nature556, no. 7700 (2018): 185-190.

[5] R. J. Clément, Z. Lun, and G. Ceder, “Cation-Disordered Rocksalt Transition Metal Oxides and Oxyfluorides for High Energy Lithium-ion Cathodes,” Energy & Environmental Science13, no. 2 (2020): 345-373.

[6] Z. Lun, B. Ouyang, D. H. Kwon, et al., “Cation-Disordered Rocksalt-Type High-Entropy Cathodes for Li-ion Batteries,” Nature Materials20, no. 2 (2021): 214-221.

[7] H. M. Hau, T. Holstun, E. Lee, et al., “Disordered Rocksalts as High-Energy and Earth-Abundant Li-ion Cathodes,” Advanced Materials (2025): 2502766, https://doi.org/10.1002/adma.202502766.

[8] H. Li, R. Fong, M. Woo, et al., “Toward High-Energy Mn-Based Disordered-Rocksalt Li-ion Cathodes,” Joule6, no. 1 (2022): 53-91.

[9] Y. Huang, Y. Dong, Y. Yang, et al., “Integrated Rocksalt-Polyanion Cathodes With Excess Lithium and Stabilized Cycling,” Nature Energy9 (2024): 1497-1505.

[10] J. Lee, J. K. Papp, R. J. Clément, et al., “Mitigating Oxygen Loss to Improve the Cycling Performance of High Capacity Cation-Disordered Cathode Materials,” Nature Communications8, no. 1 (2017): 981.

[11] D. A. Kitchaev, Z. Lun, W. D. Richards, et al., “Design Principles for High Transition Metal Capacity in Disordered Rocksalt Li-ion Cathodes,” Energy & Environmental Science11, no. 8 (2018): 2159-2171.

[12] Z. Lun, B. Ouyang, Z. Cai, et al., “Design Principles for High-Capacity Mn-Based Cation-Disordered Rocksalt Cathodes,” Chem6, no. 1 (2020): 153-168.

[13] B. Ouyang, N. Artrith, Z. Lun, et al., “Effect of Fluorination on Lithium Transport and Short-Range Order in Disordered-Rocksalt-Type Lithium-ion Battery Cathodes,” Advanced Energy Materials10, no. 10 (2020): 1903240.

[14] N. J. Szymanski, Y. Zeng, T. Bennett, et al., “Understanding the Fluorination of Disordered Rocksalt Cathodes Through Rational Exploration of Synthesis Pathways,” Chemistry of Materials34, no. 15 (2022): 7015-7028.

[15] Y. Huang, Y. Dong, S. Li, et al., “Lithium Manganese Spinel Cathodes for Lithium-ion Batteries,” Advanced Energy Materials11, no. 2 (2021): 2000997.

[16] M. M. Thackeray, “Spinel Electrodes for Lithium Batteries,” Journal of the American Ceramic Society82, no. 12 (1999): 3347-3354.

[17] Z. Lun, B. Ouyang, D. A. Kichaev, et al., “Improved Cycling Performance of Li-Excess Cation-Disordered Cathode Materials Upon Fluorine Substitution,” Advanced Energy Materials9, no. 2 (2019): 1802959.

[18] C. M. Julien and M. Massot, “Lattice Vibrations of Materials for Lithium Rechargeable Batteries III. Lithium Manganese Oxides,” Materials Science and Engineering: B100, no. 3 (2003): 69-78.

[19] J. Wu, G. K. P. Dathar, C. Sun, et al., “In Situ Raman Spectroscopy of LiFePO₄: Size and Morphology Dependence During Charge and Self-Discharge,” Nanotechnology24, no. 42 (2013): 424009.

[20] E. Markevich, R. Sharabi, O. Haik, et al., “Raman Spectroscopy of Carbon-Coated LiCOPO₄ and LiFePO₄ Olivines,” Journal of Power Sources196, no. 15 (2011): 6433-6439.

[21] J. D. Pless, T. J. Garino, J. E. Maslar, and T. M. Nenoff, “Tunable Conductivity of Collapsed Sandia Octahedral Molecular Sieves,” Chemistry of Materials19, no. 20 (2007): 4855-4863.

[22] J. M. Jehng and I. E. Wachs, “Structural Chemistry and Raman Spectra of Niobium Oxides,” Chemistry of Materials3, no. 1 (1991): 100-107.

[23] H. Ji, J. Wu, Z. Cai, et al., “Ultrahigh Power and Energy Density in Partially Ordered Lithium-ion Cathode Materials,” Nature Energy5, no. 3 (2020): 213-221.

[24] M. M. Thackeray, W. I. F. David, P. G. Bruce, and J. B. Goodenough, “Lithium Insertion Into Manganese Spinels,” Materials Research Bulletin18, no. 4 (1983): 461-472.

[25] W. J. Zhang, “Structure and Performance of LiFePO₄ Cathode Materials: A Review,” Journal of Power Sources196, no. 6 (2011): 2962-2970.

[26] M. Yoon, Y. Dong, J. Hwang, et al., “Reactive Boride Infusion Stabilizes Ni-Rich Cathodes for Lithium-ion Batteries,” Nature Energy6, no. 4 (2021): 362-371.

[27] D. K. Kim, P. Muralidharan, H. W. Lee, et al., “Spinel LiMn₂O₄ Nanorods as Lithium-ion Battery Cathodes,” Nano Letters8, no. 11 (2008): 3948-3952.

[28] G. Assat and J. M. Tarascon, “Fundamental Understanding and Practical Challenges of Anionic Redox Activity in Li-ion Batteries,” Nature Energy3, no. 5 (2018): 373-386.

[29] J. Hong, W. E. Gent, P. Xiao, et al., “Metal-Oxygen Decoordination Stabilizes Anion Redox in Li-Rich Oxide,” Nature Materials18, no. 3 (2019): 256-265.

[30] Z. Zhu, D. Yu, Y. Yang, et al., “Gradient Li-Rich Oxide Cathode Particles Immunized Against Oxygen Release by a Molten Salt Treatment,” Nature Energy4, no. 12 (2019): 1049-1058.

[31] T. Y. Huang, M. J. Crafton, Y. Yue, W. Tong, and B. D. McCloskey, “Deconvolution of Intermixed Redox Processes in Ni-Based Cation-Disordered Li-Excess Cathodes,” Energy & Environmental Science14, no. 3 (2021): 1553-1562.

[32] T. Y. Huang, Z. Cai, M. J. Crafton, et al., “Quantitative Decoupling of Oxygen-Redox and Manganese-Redox Voltage Hysteresis in a Cation-Disordered Rock Salt Cathode,” Advanced Energy Materials13, no. 21 (2023): 2300241.

[33] B. H. Toby and R. B. Von Dreele, “GSAS-II: The Genesis of a Modern Open-Source All Purpose Crystallography Software Package,” Journal of Applied Crystallography46, no. 2 (2013): 544-549.

RIGHTS & PERMISSIONS

2025 The Author(s). Interdisciplinary Materials published by Wuhan University of Technology and John Wiley & Sons Australia, Ltd.