Delicate lattice modulation enables superior Na storage performance of Na3V2(PO4)3 as both an anode and cathode material for sodium-ion batteries: understanding the role of calcium substitution for vanadium. Issue 16 (2nd April 2019)

• Record Type: Journal Article
• Authors: Zhao, Lina; Zhao, Hailei; Du, Zhihong; Wang, Jie; Long, Xuanyou; Li, Zhaolin; Świerczek, Konrad
• Is Part Of: Journal of materials chemistry. Volume 7:Issue 16(2019)
• Page Start: 9807
• Page End: 9814
• Publication Date: 2019-04-02
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c9ta00869a
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : High-performance sodium storage in Na3 V2 (PO4 )3 is realized by elaborate lattice modulation by Ca substitution for V. Abstract : Na3 V2 (PO4 )3 with a 3D open NASICON framework can accommodate a wide range of Na contents, which makes it capable of working as both a cathode and anode material. However, severe capacity degradation and inferior rate capability resulting from low electronic/ionic conductivities and poor structural stability have hindered its practical implementation. Herein, excellent sodium storage performance of Na3 V2 (PO4 )3 is realized by delicate lattice modulation. Aliovalent Ca 2+ substitution for V 3+ increases both the electronic and ionic conductivities by producing electronic defects and enlarging the sodium ion migration channels. DFT calculations reveal that the fifth Na ion intercalation/deintercalation produces a large lattice volume change, which is possibly the origin of the poor redox reaction reversibility of Na3 V2 (PO4 )3 at low potential (∼0.3 V vs. Na + /Na). The Ca 2+ doping enhances significantly the structural stability to suppress the large crystal lattice distortion during the anode reaction process. The multiple effects enable superior rate-capability and ultralong cycle-life of Ca-doped Na3 V2 (PO4 )3 as both a cathode and anode material. The symmetric full cell constructed with the optimized Na3 V1.95 Ca0.05 (PO4 )3 @C electrode delivers a very high energy density of 166 W h kg −1 and an exceptional cycling stability (0.02% capacity decay per cycle over 2000 cycles at 10C rate). This study provides a feasible strategy for obtaining high-rate and long cycle-life electrode materials for high-efficiency energy storage.