A research team from Huazhong University of Science and Technology has developed a novel orbital modulation strategy to suppress anti-site defects in NASICON-type Na 3 MnTi(PO 4 ) 3 cathode for sodium-ion batteries. By Li doping to construct Li – O – Mn configuration, the strategy effectively enhances Mn – O covalent interaction and elevates Mn defect formation energy, thus eliminating voltage hysteresis caused by anti-site defects. The optimized Na 2.97 Li 0.03 MnTi(PO 4 ) 3 cathode achieves ultra-long cycling stability, excellent rate performance and wide-temperature adaptability, and the assembled pouch-type full cell further verifies its practical application potential. This study provides a new electronic structure regulation approach for the design of high-performance sodium-ion battery cathodes, paving the way for the development of low-cost and sustainable energy storage technologies.
Sodium-ion batteries (SIB) have emerged as a promising alternative to lithium-ion batteries (LIB) for large-scale energy storage due to the abundant sodium resources, low cost and similar electrochemical reaction mechanisms. NASICON-type phosphates, especially Na 3 MnTi(PO 4 ) 3 , are considered as ideal cathode materials for SIB by virtue of their three-dimensional open ion diffusion channels, high structural stability, wide operating voltage window and high theoretical specific capacity (176 mAh g⁻ 1 ). However, the intrinsic anti-site defects formed by Mn ions occupying Na2 vacancies in Na 3 MnTi(PO 4 ) 3 have become a key bottleneck restricting its electrochemical performance. These defects not only cause severe voltage hysteresis and irreversible capacity loss, but also hinder Na⁺ diffusion kinetics, leading to poor rate performance and cycling stability of the cathode. Traditional modification strategies such as non-stoichiometric synthesis and high-valent cation doping only alleviate the problem through indirect charge compensation or reducing Na vacancies, failing to fundamentally reveal and regulate the electronic origin of anti-site defects formation, resulting in suboptimal electrochemical performance of the modified materials. Therefore, developing a precise regulation strategy to inhibit the formation of anti-site defects from the electronic structure level is crucial for the practical application of NASICON-type Na 3 MnTi(PO 4 ) 3 cathode.
The Solution: The present study proposes a method based on e g orbital modulation for the suppression of anti-site defects in Na 3 MnTi(PO 4 ) 3 . This method suggests a substantial advancement within the field, as it identifies the electronic origin of manganese instability in Na 3 MnTi(PO 4 ) 3 rather than compensating for it through long-range electrostatic effects. This work reveals that the Li-O-Mn configuration facilitates the electron occupation of the Mn 3 d - e g orbital. This strengthens the hybridization between the Mn (3 d - e g ) and O (2 p ) orbitals, thereby increasing the Mn–O covalency. Consequently, the defect formation energy of Mn increases, which in turn effectively reduces the anti-site defects in Na 2.97 Li 0.03 MnTi(PO 4 ) 3 . The Na 2.97 Li 0.03 MnTi(PO 4 ) 3 cathode maintains high phase transformation integrity during the charge-discharge process with low volume change (ΔV=5.8%). The resulting Na 2.97 Li 0.03 MnTi(PO 4 ) 3 electrode shows a high-capacity retention rate of 89.6% after 3,000 cycles at 10C within a voltage window of 1.5-4.3 V ( vs . Na⁺/Na) and operates effectively across a wide temperature range from −30 to 40 °C. The pouch-type full cell using Na 2.97 Li 0.03 MnTi(PO 4 ) 3 cathode further demonstrates its practical application.
The Future: Future research will focus on extending this orbital modulation strategy to other polyanionic cathode materials suffering from cation disorder and anti-site defects problems, and developing universal descriptors linking orbital occupancy, metal-oxygen covalency and defect formation energy to accelerate the rational design of next-generation high-voltage, high-capacity and long-life sodium-ion battery cathodes. From a practical industrial perspective, the research team will further optimize the synthesis process, realize the large-scale preparation of Li-doped NASICON-type cathodes with precise electronic structure regulation at low cost, and combine with high-performance electrolytes and modified anodes to construct high-performance sodium-ion battery full cells, further improving the energy density, cycling life and environmental adaptability of the battery system, and promoting the industrialization and commercialization of sodium-ion batteries in large-scale energy storage, electric vehicles and portable electronic devices.
The Impact: This work innovatively proposes an orbital modulation strategy from the electronic structure level, which fundamentally solves the key problem of anti-site defects in NASICON-type Na 3 MnTi(PO 4 ) 3 cathode, and for the first time reveals the intrinsic mechanism of Mn–O covalent interaction regulation on anti-site defects formation. The optimized Na 2.97 Li 0.03 MnTi(PO 4 ) 3 cathode achieves the comprehensive improvement of voltage hysteresis elimination, rate performance, cycling stability and wide-temperature adaptability, providing a new material system for high-performance sodium-ion batteries. More importantly, this study establishes a new paradigm of electronic structure regulation for cathode materials, which not only provides a new research idea for the modification of NASICON-type phosphates, but also has important reference significance for the design and development of other metal oxide and polyanionic cathode materials with cation disorder problems, accelerating the development of low-cost, high-performance and sustainable sodium-ion battery technology, and providing strong technical support for the global energy transition and carbon neutrality goal.
The research has been recently published in the online edition of Materials Futures , a prominent international journal in the field of interdisciplinary materials science research.
Reference: Jiandong Zhang, Zhaoshi Yu, Liyuan Tian, Yanbin Zhu, Muqin Wang, Pengkun Gao, Yali Zhang, Naiqing Zhang, Deyu Wang, Yan Shen, Mingkui Wang. Orbital modulation to restrain anti-site defects in NASICON cathode for high-performance sodium-ion batteries[J]. Materials Futures . DOI: 10.1088/2752-5724/ae44b2
Materials Futures
Orbital Modulation to Restrain Anti-Site Defects in NASICON Cathode for High-Performance Sodium-Ion Batteries
11-Feb-2026