Fabrication of porous Na3V2(PO4)3/reduced graphene oxide hollow spheres with enhanced sodium storage performance
2020
Xu, Jingyi | Gu, Erlong | Zhang, Zhuangzhuang | Xu, Zhenhua | Xu, Yifan | Du, Yichen | Zhu, Xiaoshu | Zhou, Xiaosi
Sodium-ion batteries (SIBs) have long been recognized as a potential substitute for lithium-ion batteries, while their practical application is greatly hindered owing to the absence of suitable cathode materials with improved rate capability and prolonged cycling life. Na₃V₂(PO₄)₃ (NVP) has drawn extensive attention among the cathode materials for SIBs because of its fast Na⁺-transportable framework which enables high-speed charge transfer, but the poor electric conductivity of NVP significantly restricts the Na⁺ diffusion. To tackle this issue, in this work, porous NVP/reduced graphene oxide hollow spheres (NVP/rGO HSs) are constructed via a spray drying strategy. Due to the unique porous hollow architecture, the synthesized compound manifests a high reversible capacity of 116 mAh g⁻¹ at 1 C (1 C = 118 mA g⁻¹), an outstanding high-rate capability of 107.5 mAh g⁻¹ at 10 C and 98.5 mAh g⁻¹ at 20 C, as well as a stable cycling performance of 109 mAh g⁻¹ after 400 cycles at 1 C and 73.1 mAh g⁻¹ after 1000 cycles at 10 C. Moreover, galvanostatic intermittent titration technique demonstrates that the Na⁺ diffusion coefficient of NVP/rGO HSs is an order of magnitude larger than the pristine NVP. The remarkable electrochemical properties of NVP/rGO HSs in full cells further enable it a potential cathode for SIBs.
显示更多 [+] 显示较少 [-]