Theoretical studies of the optical and EPR spectra for V3+ in Y2O3 crystal

Feng, Wenlin; Wu, Xiao‐Xuan; Zheng, Wen-Chen

doi:10.1016/j.jlumin.2008.01.018

Cited by 7 publications

(1 citation statement)

References 23 publications

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“…From the EPR spectrum of the Na 3 V 2 (PO 4 ) 3 /C, it is observed that there is a main resonance line at the magnetic field of 3370 G, corresponding to the electron's so-called g-factor around 1.95, which is consistent with the calculated g value of V 3+ in previous study. 46 According Zhang et al's work, 47 the signal intensity of EPR is related to the concentration of unpaired electrons. Compared to the Na 3 V 2 (PO 4 ) 3 /C, the signal intensity of the Na 3 V 1.95 Cu 0.05 (PO 4 ) 3 /C is much stronger, which could be attributed to the unpaired electrons trapped on V O ¨by Cu doping.…”

Section: Resultsmentioning

confidence: 99%

High Rate Performance of Na₃V_2-xCu_x(PO₄)₃/C Cathodes for Sodium Ion Batteries

Zhang¹,

Feng²,

Xu³

et al. 2017

J. Electrochem. Soc.

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The Na 3 V 2-x Cu x (PO 4 ) 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 Na 3 V 2 (PO 4 ) 3 /C are characterized by XRD, SEM, XPS, EPR and electrochemical measurements. The results show that the Na 3 V 1.95 Cu 0.05 (PO 4 ) 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 Na 3 V 2 (PO 4 ) 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 Na 3 V 2 (PO 4 ) 3 system.

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Section: Resultsmentioning

confidence: 99%