Effect of Depth of Discharge on the Performance of Zn-Mn and Zn-Ni Battery

Abstract

In this communication, the zinc anode electrode was prepared by electroplating. MnO2 cathodes and Ni(OH)2 cathode electrodes were prepared by the pressing process. KOH 6 M with 40%ZnO were used as the electrolyte solution of a battery. X-ray diffraction (XRD) was used to study the complexation of cathode electrodes. The Fourier transform infrared spectroscopy (FTIR) analysis showed some peaks which ascertain chemical interlinking of ZnMnO2 and Zn-Ni(OH)2 on cathode electrodes. After performance testing, morphology characterization of zinc anode electrode was performed by scanning electron microscopy (SEM). The electrodes were tested for performance by a battery analyzer for 100 cycles with a depth of discharge (DOD) at 10%, 20%, 40%, and 80%. It was found that zinc electrodes had branching of a dendrite, which quickly grew at a high depth of discharge. The depth of discharge influenced dendrite growth and the battery performance during cell discharging at high DOD. The Zn anode was damaged due to the excessive dissolution of Zn+ in the electrolyte, causing the decay of the Zn anode. On the other hand, during cell charging, Zn+ was not uniformly deposited on the anode, resulting in dendrite branching. Zinc electrode in Zn-MnO2 cell had more dendrite than zinc electrode in Zn-Ni(OH)2 cell at 10%DOD. The results also showed higher efficiency of 99.08% and better stability for Zn-Ni(OH)2 than Zn-MnO2 cells in similar conditions. This was due to the fact that during cell discharge. Mn+ in the electrolyte continuously reacts with Zn+ to form other complex compounds. On the contrary, Ni(OH)2 cathode exhibited better recyclability than MnO2 cathode. Therefore, Ni(OH)2 cathode offers excellent potential for use as a cathode electrode because it can be used at high DOD. Another advantage of Ni(OH)2 cathode is that it can be prepared from a simple process by making use of readily available non-toxic materials.