储能科学与技术 ›› 2023, Vol. 12 ›› Issue (8): 2370-2381.doi: 10.19799/j.cnki.2095-4239.2023.0177

• 储能材料与器件 • 上一篇    下一篇

Nb掺杂Na3V2O2PO42F空心微球钠离子电池正极材料的制备与性能

张梓楠1,2(), 陈剑1()   

  1. 1.中国科学院大连化学物理研究所,辽宁 大连 116023
    2.中国科学院大学,北京 100049
  • 收稿日期:2023-03-27 修回日期:2023-04-08 出版日期:2023-08-05 发布日期:2023-08-23
  • 通讯作者: 陈剑 E-mail:zinan@dicp.ac.cn;chenjian@dicp.ac.cn
  • 作者简介:张梓楠(1998—),女,硕士研究生,研究方向为钠离子电池正极材料,E-mail:zinan@dicp.ac.cn
  • 基金资助:
    国家科技计划项目(BX221C012)

Preparation and property evaluation of Nb-doped Na3V2O2PO42F hollow microspheres as cathode materials for sodium-ion batteries

Zinan ZHANG1,2(), Jian CHEN1()   

  1. 1.Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China
    2.University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2023-03-27 Revised:2023-04-08 Online:2023-08-05 Published:2023-08-23
  • Contact: Jian CHEN E-mail:zinan@dicp.ac.cn;chenjian@dicp.ac.cn

摘要:

Na3V2O2(PO4)2F(NVOPF)具有较稳定的聚阴离子结构、较高的工作电压和理论比能量,是一种具有良好应用前景的钠离子电池正极材料。但该材料在合成过程中易发生不规则团聚,且本征电导率低,导致材料的实际比容量较小,倍率性能和循环性能有待提高。通过离子掺杂以及合成具有微纳结构的材料可以有效提高这类材料的结构稳定性和电导率。本工作首次报道了多元醇辅助水热法合成具有空心微球结构的Nb5+掺杂NVOPF[NVNOPF,Na3V2-x Nb x O2(PO4)2F(0≤x≤0.15)]材料。所制备的NVOPF和NVNOPF是尺寸为0.7~1.0 μm的具有中空结构的微球。可以发现微球由尺寸小于100 nm的纳米颗粒组成。纳米颗粒缩短钠离子的扩散距离,并且缓冲了由于钠离子的嵌入/脱出所导致的体积变化,提高了材料的循环稳定性。同时,掺杂Nb5+增大了NVOPF的晶格参数,增大了Na+扩散通道,将Na+在NVOPF中的固相扩散系数由Na3V2O2(PO4)2F的6.46×10-16 cm2/s提高至Na3V1.90Nb0.10O2(PO4)2F的3.52×10-15 cm2/s。Na3V1.90Nb0.10O2(PO4)2F材料以0.1 C倍率放电,首次放电比容量达126.4 mAh/g;以10 C倍率放电,初始比容量为98.1 mAh/g,500周循环后的容量保持率为95.2%,明显优于未掺杂材料的66.8%。研究结果显示掺杂Nb5+的空心球形微纳结构有效提高了NVOPF材料的电化学性能和循环稳定性。

关键词: 钠离子电池正极材料, Na3V2O2(PO4)2F, 多元醇辅助水热法, 空心微球, 铌掺杂

Abstract:

Na3V2O2(PO4)2F(NVOPF) is a cathode material with potential application prospects in sodium-ion batteries. This is due to its suitably stable polyanion structure, high operating voltage, and high theoretical specific capacity. However, the intrinsic conductivity of the material is low, and it is prone to irregular agglomeration during the synthesis process, resulting in low actual specific capacity and unsatisfactory rate and cycling performances. Ion doping and micro/nanostructured materials have been found to benefit the intrinsic conductivity and stability of the material. This work, for the first time, reports the synthesis of Nb5+-doped NVOPF(NVNOPF, Na3V2-x Nb x O2(PO4)2F (0≤x≤0.15)) material with a hollow microspheric structure by the polyol-assisted hydrothermal method. The as-prepared NVOPF and NVNOPF materials were microspheres with sizes of 0.7-1.0 μm with hollow structures. The microspheres were found to be composed of nanoparticles of with sizes <100 nm. Nanoparticles shortened the diffusion distance between sodium ions, buffered the volume change caused by the intercalation/extraction of sodium ions, and improved the material cycling stability. Meanwhile, doping Nb5+ increased the lattice parameters of NVNOPF and enlarged the Na+ diffusion pathway. The solid-phase diffusion coefficient of Na+ in the material increased from 6.46×10-16 for Na3V2O2(PO4)2F to 3.52×10-15 cm2/s for Na3V1.90Nb0.10O2(PO4)2F. The discharge specific capacity of Na3V1.90Nb0.10O2(PO4)2F was 126.4 mAh/g (0.1 C rate) and 98.1 mAh/g (10 C rate). After 500 cycles of charge and discharge at the 10 C rate, the capacity retention was 95.2%, which is better than that of the undoped material (66.8%). The results showed that Nb-doped and hollow spherical micro-/nanostructures could effectively improve the electrochemical performance and cyclic stability of NVOPF.

Key words: cathode material for sodium ion battery, Na3V2O2(PO4)2F, polyol assisted hydrothermal method, hollow microspheres, niobium doping

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