Author(s): Kunyang Geng, Shuangxue Li, Guohui Yang, Qimeng Du, Zenghui He, Xueling Wu, Siru Chen, Mingli Jiao, Yaomin Zhao

Doi: 10.7508/aiem.01.2025.35.42

This is an open access article distributed under the Creative Commons Attribution License CC BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

To address the issue of low intrinsic conductivity in sodium-ion battery cathode material Na₃V₂(PO₄)₃ (NVP), a sol-gel method combined with carbon nanotube (CNTs) composite technology was employed to successfully synthesize K⁺, Al³⁺, and SiO₄^4- triple-doped NVP/C@CNTs composites. Systematic structural characterization revealed that the prepared composites exhibit a typical NASICON structure. The tripledoping strategy induced lattice expansion, which lowered the Na⁺ migration barrier, while grain refinement shortened the ion diffusion pathway. Additionally, CNTs incorporation effectively suppressed NVP particle agglomeration and constructed a three-dimensional conductive network, significantly enhancing the overall electrochemical performance of NVP-based materials. The results demonstrate that the triple-doped K_0.04Na_3.06V_1.96Al_0.04(PO₄)_2.9(SiO₄)_0.1/C@5%CNTs composite achieves an initial discharge specific capacity of 114.18 mAh g-1 at 0.1C (reaching 97.09% of the theoretical capacity), with a capacity retention of 95.36% (104.80 mAh g^-1) after 200 cycles at 1C and 93.25% capacity retention at 10C (relative to 0.3C), demonstrating superior electrochemical performance. The synergistic strategy of triple-doping combined with CNT compositing provides a novel approach for developing high-performance cathode materials for sodium-ion batteries.

KEYWORDS:
Sodium Ion Battery, Sodium Vanadium Phosphate Composite, Multi-Ion Doping, Synergy Effect, Sodium Storage Performance