Sodium vanadate nanoflowers/rGO composite as a high-rate cathode material for sodium-ion batteries
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Herein, Na5V12O32 has a low conductivity, which restricts its electrochemical performance. In order to use Na5V12O32 in practical sodium-ion batteries (SIBs), nanoflowers were prepared hydrothermally to enhance the electronic conductivity with the increasing of the effective surface area. Each nanoflower has 2D nanosheets with the thickness of ca. 10 nm and length up to 150 nm. Na5V12O32 nanoflowers were then embedded with reduced graphene oxide (rGO) by solid-state reaction process, which gives rise to fast electron transfer. The cathodic behaviour of 5–15 wt% rGO composites with Na5V12O32 nanoflowers is investigated. As a cathode material for SIBs, Na5V12O32 nanoflowers/rGO–10 wt% composite has a redox potential ca. 2.9 V versus Na+/Na and exhibits an excellent reversible cycling with initial discharge capacity of 142 mAh g−1 at a rate of 5C. In addition, Na5V12O32 nanoflowers/rGO–10 wt% composite has a tap density of 3 g cm−3 and volumetric energy density 1242 Wh L−1. These preliminary results indicate that the Na5V12O32 nanoflowers/rGO–10 wt% composite is a promising cathode candidate for SIBs.
This work was supported by the National Nature Science Foundation of China (Nos. 11674258, 51572205), International Science & Technology Cooperation Program of China (No. 2013DFR50710), the Fundamental Research Funds for the Central Universities (No. 2017II22GX), and China Scholarship Council (No. 2013GXZ980). Thanks for the measurements supporting from Center for Materials Research and Analysis at Wuhan University of Technology (WUT).