High Rate Performance of Na3V2-xCux(PO4)3/C Cathodes for Sodium Ion Batteries. Issue 14 (17th November 2017)

• Record Type: Journal Article
• Authors: Zhang, Dongyun; Feng, Ping; Xu, Bingyan; Li, Zhen; Qiao, Jin; Zhou, Jiang; Chang, Chengkang
• Is Part Of: Journal of the Electrochemical Society. Volume 164:Issue 14(2017)
• Page Start: A3563
• Page End: A3569
• Publication Date: 2017-11-17
• Subjects: Batteries -- Cathode -- Cu doping; Electrochemistry -- Periodicals; 541.3705
• DOI: 10.1149/2.0381714jes
• Languages: English
• ISSNs: 0013-4651

Abstract

Abstract : The Na3 V2-x Cux (PO4 )3 /C (x = 0, 0.01, 0.03, 0.05 and 0.07) cathodes have been prepared by ballmilling and spray-drying assisted high-temperature solid-state reaction. The effects of Cu doping on Na3 V2 (PO4 )3 /C are characterized by XRD, SEM, XPS, EPR and electrochemical measurements. The results show that the Na3 V1.95 Cu0.05 (PO4 )3 /C delivers the highest discharge capacity of 90.6 mAh g −1 at 50 C and superior cyclic retention of 88.2% after 2000 cycles at 20 C, which could be mainly attributed to the high electronic conductivity (7.2 × 10 −2 S cm −1 ) and Na ion diffusion coefficient (1.695 × 10 −12 cm 2 s −1 ). The introduction of Cu 2+ into the Na3 V2 (PO4 )3 /C lattice produces oxygen vacancies with accompanying conduction electrons, which lead to the enhanced electronic conductivity and Na ion diffusion coefficient. Besides, inactive Cu 2+ acts as a pillar to reduce the negative effects caused by the volume shrinking/swelling during the Na + extraction/insertion, resulting in increased cycle stability of the Cu-doped Na3 V2 (PO4 )3 system.