The electrochemical performance improvement of LiMn2O4/Zn based on zinc foil as the current collector and thiourea as an electrolyte additive

Abstract

The polished commercial zinc foil as the current collector and thiourea (TU) as the electrolyte additive are studied systematically to improve the performance of LiMn2O4/Zn aqueous battery. The results show that the coulombic efficiency and the cycling performance are significantly improved by using the polished zinc foil as the anode current collector. Moreover, the TU addition increases the cycling performance of LiMn2O4/Zn battery and decreases the float charge current density of the battery at room as well as high temperature. X-ray diffraction (XRD) and scanning electron microscopy (SEM) tests confirm that there is nearly no effect of TU in the electrolyte on the crystal structure of LiMn2O4 electrode. However, the addition of TU has an indirect effect on the morphology. Cyclic voltammetry (CV) and deposition–dissolution measurement demonstrate that TU is stable on the cathode electrode and it is able to adsorb to the surface of the zinc anode current collector. As such, the deposition–dissolution efficiency and energy efficiency are improved, which also can be attributed to faster deposition–dissolution and smaller self-discharge process of zinc.