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Int. J. Electroactive Mater. 12 (2024) 98-106

Investigating the Influence of Hubbard U on Electronic Properties and Intercalation Voltage in LiFePO4 Cathode Materials for Lithium-Ion Batteries using First-Principles Study

Fatin Nabilah Sazman1*, Fadhlul Wafi Badrudin2, Nur Hamizah Mohd Zaki3, Shahrul Izwan Ahmad2, Mohd Hazrie Samat4, Muhammad Noor Syazwan Saimin3, Nur Ain Nabilah Mohamad Nor5, Mohd Zaid Zolkiffly6, Siti Nur Amira Shaffee6, Oskar Hasdinor Hassan3, Muhd Zu Azhan Yahya7, Mohamad Fariz Mohamad Taib5, Ainnur Sherene Kamisan5, Ainnur Izzati Kamisan6, Ab Malik Marwan Ali5

1Applied Sciences, Universiti Teknologi MARA, SHAH ALAM, Selangor, Malaysia
2Pusat Asasi Pertahanan, Universiti Pertahanan Nasional Malaysia (UPNM), Sungai Besi, Kuala Lumpur, Malaysia
3 Institute of Science (IOS), Universiti Teknologi MARA (UiTM), Shah Alam, Selangor, Malaysia
4School of Distance Education (SDE), Universiti Sains Malaysia, Gelugur, Pulau Pinang, Malaysia
5Faculty of Applied Sciences, Universiti Teknologi MARA (UiTM), Shah Alam, Selangor, Malaysia
6Renewables Technology Program PETRONAS , PETRONAS Research Sdn Bhd, Bandar Baru Bangi, Selangor, Malaysia
7Jabatan Sains Pertahanan, Universiti Pertahanan Nasional Malaysia (UPNM), Sungai Besi, Kuala Lumpur, Malaysia

*Email Address : fatinsazman29@gmail.com

Abstract : Pristine LiFePOâ‚„ (LFP) cathode materials have been analysed through first-principles calculations. The structural, electronic properties and intercalation voltage of LFP have been investigated by first-principles calculation based on the density functional theory (DFT) method. The properties of LFP were calculated using the Cambridge Serial Total Energy Package (CASTEP) computer code. Within the first-principles approach, DFT method was performed using generalized gradient approximation (GGA) for Perdew-Burke-Ernzerhof (PBE) method by applying Hubbard correction U in Fe 3d states. The GGA-PBE with U = 4.4 eV yielded a band gap of 3.755 eV which is in close agreement with the experimental value of 3.75 eV differing by only 0.13%. The results demonstrate that the inclusion of the Hubbard U parameter enhances the localization of Fe 3d states leading to a more accurate band gap prediction and an increased intercalation voltage that aligns with experimental data. Similarly, the calculated intercalation voltage with U = 3.0 eV accurately reproduced the experimental value of 3.45 V addressing the underestimation observed in standard DFT calculations without U correction. These results highlight the critical role of Hubbard U in improving the accuracy of electronic and electrochemical predictions. The increased band gap and intercalation voltage reflect enhanced electron mobility and conductivity making LFP a highly suitable cathode material for lithium-ion batteries with optimized performance.

Keywords : First-principles, Density functional theory, LiFePO4, Intercalation Voltage