TY - JOUR
T1 - Improvement in the Energy Density of Na3V2(PO4)3 by Mg Substitution
AU - Inoishi, Atsushi
AU - Yoshioka, Yuto
AU - Zhao, Liwei
AU - Kitajou, Ayuko
AU - Okada, Shigeto
N1 - Funding Information:
This work was performed under the Cooperative Research Program of “Network Joint Research Center for Materials and Devices”. We received financial support from “Elements Strategy Initiative for Catalysts & Batteries (ESICB)” program of MEXT, Japan, and The Suzuki Foundation.
Publisher Copyright:
© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
PY - 2017/11
Y1 - 2017/11
N2 - Na3V2(PO4)3, with a NASICON-type structure, is a promising cathode material for use in sodium-ion batteries based on a two-electron reaction and operating at 3.4 V. Herein, we report the synthesis of Na3+xV2-xMgx(PO4)3 (x=0.1 to 0.7) for use as a cathode material in sodium-ion batteries. In this work, Na3.2V1.8Mg0.2(PO4)3 was found to exhibit a larger reversible capacity than the theoretical capacity of undoped Na3V2(PO4)3, as a result of the larger number of Na+ in the initial composition, as well as access to the V4+/V5+ redox couple. In contrast, although Mg-rich samples such as Na3.5V1.5Mg0.5(PO4)3 showed a relatively clear plateau for the V4+/V5+ redox couple, the total discharge capacities were lower than that of the undoped Na3V2(PO4)3 because of the irreversibility in the V4+/V5+ redox region. ICP data clearly indicated that Mg2+ are stable within the NASICON structure during redox cycling and that Na+ is the charge carriers in this cathode.
AB - Na3V2(PO4)3, with a NASICON-type structure, is a promising cathode material for use in sodium-ion batteries based on a two-electron reaction and operating at 3.4 V. Herein, we report the synthesis of Na3+xV2-xMgx(PO4)3 (x=0.1 to 0.7) for use as a cathode material in sodium-ion batteries. In this work, Na3.2V1.8Mg0.2(PO4)3 was found to exhibit a larger reversible capacity than the theoretical capacity of undoped Na3V2(PO4)3, as a result of the larger number of Na+ in the initial composition, as well as access to the V4+/V5+ redox couple. In contrast, although Mg-rich samples such as Na3.5V1.5Mg0.5(PO4)3 showed a relatively clear plateau for the V4+/V5+ redox couple, the total discharge capacities were lower than that of the undoped Na3V2(PO4)3 because of the irreversibility in the V4+/V5+ redox region. ICP data clearly indicated that Mg2+ are stable within the NASICON structure during redox cycling and that Na+ is the charge carriers in this cathode.
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U2 - 10.1002/celc.201700540
DO - 10.1002/celc.201700540
M3 - Article
AN - SCOPUS:85028006268
VL - 4
SP - 2755
EP - 2759
JO - ChemElectroChem
JF - ChemElectroChem
SN - 2196-0216
IS - 11
ER -