材料科学与技术 ›› 2023, Vol. 165 ›› Issue (0): 1-7.DOI: 10.1016/j.jmst.2023.05.005

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  • 收稿日期:2023-03-18 修回日期:2023-04-25 接受日期:2023-05-04 出版日期:2023-12-01 发布日期:2023-06-02

Cr-doped Na3V2(PO4)3@C enables high-capacity with V2+/V5+ reaction and stable sodium storage

Bo Maia, Boyu Xinga, Yunfan Yuea, Nianyao Caia, Congcong Caia, Sitian Liana, Hao Fana, Mengyu Yana, Ting Zhua, Ping Hua,b, Xuewen Wanga,b,*, Liqiang Maia,b,*   

  1. aState Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China;
    bFoshan Xianhu Laboratory of the Advanced Energy Science and Technology, Guangdong Laboratory, Foshan 528216, China
  • Received:2023-03-18 Revised:2023-04-25 Accepted:2023-05-04 Online:2023-12-01 Published:2023-06-02
  • Contact: *E-mail addresses: . xwwang@whut.edu.cn (X. Wang), mlq518@whut.edu.cn (L. Mai)

Abstract: Due to its abundant sodium content and low cost, sodium-ion battery (SIB) has become an effective substitute and supplement for lithium-ion batteries, which has a broad development prospect in large-scale energy storage systems. Na-super-ionic conductor (NASICON) structural materials have stable 3D skeleton structures and open Na+ transport channels, which is a very promising SIB cathode material. But in the typical NASICON material Na3V2(PO4)3 (NVP), the number of electrons involved in NVP per formula unit is less than 2 at the stable voltage window, which limits the further improvement of battery performance. In this work, we report another NASICON structured Na3V4/3Cr2/3(PO4)3@C (NVCP@C), which is obtained by Cr-doped NVP through spray drying. By taking full advantage of the voltage platforms of V5+/4+, V4+/3+, and V3+/2+ in the window of 1.5-4.4 V, NVCP@C delivered a high discharge capacity (175 mAh g-1) and durable cyclability (86% capacity retention for 2000 cycles). In-situ X-ray diffraction results demonstrate that the reversible structural evolution accompanies by solid-solution reaction and two-phase reaction mechanisms co-exist during charge/discharge processes. When coupled with Na+ pre-embedded hard carbon (HC), the assembled NVCP@C//HC full cell delivers a high capacity (105 mAh g-1) and long cycling performance (70% after 1000 cycles). This Cr-doped NVP method offers new insights into the design of high-energy NASICON-structured cathode materials.

Key words: Sodium-ion batteries, NASICON, Na3V4/3Cr2/3(PO4)3@C, Spray drying, V2+/V5+ reaction