Electrochemical performance and reaction mechanism investigation of $V_{2}O_{5}$ positive electrode material for aqueous rechargeable zinc batteries

Qiang Fu, Jiaqi Wang, Angelina Sarapulova, Lihua Zhu, Alexander Missyul, Edmund Welter, Xianlin Luo, Ziming Ding, Michael Knapp, Helmut Ehrenberg, Sonia Dsoke
The electrochemical performance and reaction mechanism of orthorhombic V$_2$O$_5$ in 1 M ZnSO$_4$ aqueous electrolyte are investigated. V$_2$O$_5$ nanowires exhibit an initial discharge and charge capacity of 277 and 432 mA h g$^{−1}$, respectively, at a current density of 50 mA g$^{−1}$. The material undergoes quick capacity fading during cycling under both low (50 mA g$^{−1}$) and high (200 mA g$^{−1}$) currents. V$_2$O$_5$ can deliver a higher discharge capacity at 200 mA g$^{−1}$ than that
more » ... t 50 mA g$^{−1}$ after 10 cycles, which could be attributed to a different type of activation process under both current densities and distinct degrees of side reactions (parasitic reactions). Cyclic voltammetry shows several successive redox peaks during Zn ion insertion and deinsertion. In operando synchrotron diffraction reveals that V$_2$O$_5$ undergoes a solid solution and two-phase reaction during the 1st cycle, accompanied by the formation/decomposition of byproducts Zn$_3$(OH)$_2$V$_2$O$_7$·2(H$_2$O) and ZnSO$_4$Zn$_3$(OH)$_6$·5H$_2$O. In the 2nd insertion process, V$_2$O$_5$ goes through the same two-phase reaction as that in the 1st cycle, with the formation of the byproduct ZnSO$_4$Zn$_3$(OH)$_6$·5H$_2$O. The reduction/oxidation of vanadium is confirmed by in operando X-ray absorption spectroscopy. Furthermore, Raman, TEM, and X-ray photoelectron spectroscopy (XPS) confirm the byproduct formation and the reversible Zn ion insertion/deinsertion in the V$_2$O$_5$.
doi:10.3204/pubdb-2021-03318 fatcat:fklzb42lknhjpbpu73sbmnigw4