Synergetic effect of Na-doping and carbon coating on the electrochemical performances of Li 3- x Na x V 2 (PO 4 ) 3 /C as cathode for lithium-ion batteries
Carbon coated Li Na V (PO ) /C ( = 0.04, 0.06, 0.10, 0.12, 0.18) cathode materials for lithium-ion batteries were synthesized a simple carbothermal reduction reaction route using methyl orange as the reducing agent, which also acted as the Na and carbon sources. The influence of various Na-doping le...
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Published in | RSC advances Vol. 9; no. 15; pp. 8222 - 8229 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
England
12.03.2019
|
Online Access | Get full text |
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Summary: | Carbon coated Li
Na
V
(PO
)
/C (
= 0.04, 0.06, 0.10, 0.12, 0.18) cathode materials for lithium-ion batteries were synthesized
a simple carbothermal reduction reaction route using methyl orange as the reducing agent, which also acted as the Na and carbon sources. The influence of various Na-doping levels on the structure and electrochemical performance of the Li
Na
V
(PO
)
/C composites was investigated. The valence state of vanadium, the form of residual carbon and the overall morphology of the Li
Na
V
(PO
)
/C, which showed the highest initial specific discharge capacity of 128 mA h g
at the current density of 0.1C (1C = 132 mA g
) among this series of composites, were further examined by X-ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy and high-resolution transmission electron microscopy, respectively. The results indicated that a well crystallized structure of Na-doped Li
Na
V
(PO
)
coated by a carbon matrix is obtained. In the further electrochemical measurements, the Li
Na
V
(PO
)
/C cathode material shows superior discharge capacities of 124, 118, 113, 106 and 98 mA h g
at 0.3, 0.5, 1, 2 and 5C, respectively. High capacity retention of 97% was obtained after 1100 cycles in long-term cyclic performance tests at 5C. The reason for such a promising electrochemical performance of the as-prepared Li
Na
V
(PO
)
/C has also been explored, which revealed that the synergetic effect of the Na-doping and carbon coating provide enlarged Li
diffusion channels and the increased electronic conductivity. |
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ISSN: | 2046-2069 2046-2069 |
DOI: | 10.1039/C8RA10646K |