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Modulation of the Crystal Structure and Ultralong Life Span of a Na3V2(PO4)3-Based Cathode for a High-Performance Sodium-Ion Battery by Niobium–Vanadium Substitution
Industrial & Engineering Chemistry Research ( IF 3.8 ) Pub Date : 2020-11-20 , DOI: 10.1021/acs.iecr.0c04187
Linnan Bi 1 , Xiaoqing Liu 1 , Xiaoyan Li 1 , Bingbing Chen 2 , Qiaoji Zheng 1 , Fengyu Xie 1 , Yu Huo 1 , Dunmin Lin 1
Affiliation  

Building better batteries with low cost, long life, and safety can effectively meet the diverse energy demands. Na3V2(PO4)3 (NVP) is a potential cathode in energy storage systems due to its stable crystal structure, high-voltage platform, and rapid migration rate of Na+. Nevertheless, its poor conductivity results in inferior electrochemical properties. Herein, the high-valence niobium (Nb5+) as a dopant can regulate the crystal structure of NVP and act as an activator to catalyze the formation of the graphitization carbon layer, which shortens the electron/ion diffusion pathway and enhances the electrochemical kinetics. Density functional calculations show that Nb5+ doping decreases the band gap energy and promotes electron transport. Physical and chemical characterizations prove that Nb5+ doping induces the lattice distortion of NVP. Cyclic voltammetry and electrochemical impedance tests show that Nb5+ doping promotes Na+ diffusion. Finally, the optimal NVP/Nb-0.3 delivers an excellent performance of 103.8 mAh g–1 with a capacity retention of 92.3% at 1 C for 200 cycles, a rate performance of 99.6 mAh g–1 at 20 C, and cycling stability at 50 C for 6000 cycles with a capacity retention of 72.7%. This modification strategy of cathode materials provides an important reference for optimizing battery performance.

中文翻译:

铌钒置换对高性能钠离子电池基于Na 3 V 2(PO 43的阴极的晶体结构和超长寿命的调节

用低成本,长寿命和安全性制造更好的电池可以有效地满足各种能源需求。Na 3 V 2(PO 43(NVP)由于其稳定的晶体结构,高压平台和Na +的快速迁移,是储能系统中的潜在阴极。然而,其差的电导率导致较差的电化学性能。在此,高价铌(Nb 5+)作为掺杂剂可以调节NVP的晶体结构,并作为活化剂来催化石墨化碳层的形成,从而缩短了电子/离子扩散路径并增强了电化学动力学。 。密度泛函计算表明Nb 5+掺杂会降低带隙能量并促进电子传输。物理和化学表征证明,Nb 5+掺杂会引起NVP的晶格畸变。循环伏安法和电化学阻抗测试表明,Nb 5+掺杂促进Na +扩散。最后,最佳的NVP / Nb-0.3具有出色的103.8 mAh g –1的性能,在1 C下200个循环的容量保持率为92.3%,在20 C时的速率性能为99.6 mAh g –1,在30°C时的循环稳定性在50 C下进行6000次循环,容量保持率为72.7%。正极材料的这种改性策略为优化电池性能提供了重要参考。
更新日期:2020-12-02
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