Zinc Electrode Morphology Evolution in High Energy Density Nickel-Zinc Batteries

Abstract

Prismatic Nickel-Zinc (NiZn) batteries with energy densities higher than 100 Wh kg −1 were prepared using Zn electrodes with different initial morphologies. The effect of initial morphology of zinc electrode on battery capacity was investigated. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) reveal that initial morphology of zinc electrode changes drastically after a few charge/discharge cycles regardless of initial ZnO powder used. ZnO electrodes prepared using ZnO powders synthesized from ZnCl 2 and Zn(NO 3 ) 2 lead to average battery energy densities ranging between 92 Wh kg −1 and 109 Wh kg −1 while using conventional ZnO powder leads to a higher energy density, 118 Wh kg −1 . Average discharge capacities of zinc electrodes vary between 270 and 345 mA g −1 , much lower than reported values for nano ZnO powders in literature. Higher electrode surface area or higher electrode discharge capacity does not necessarily translate to higher battery energy density.

Binder Effect on Electrochemical Performance of Zinc Electrodes For Nickel-Zinc Batteries

“…Similar to samples A, the weak peaks of calcium zincate are detected in all samples B. It can be concluded that is no difference between all zinc electrodes after third discharge and electrode paste before first charge, and the result corresponds to previous report in the literature [32]. …”

“…Also, the commercial ZnO showed a wide range of particle size distribution with most of the particles having needle-like shapes as well as having tripod and nanorod shapes [32].…”

“…The increase in the surface area of zinc electrode exhibits the increase in materials utilization and power density and the reduction of passivation at high discharge rates in NiZn batteries [23,32]. High surface area of zinc electrode can improve battery performance due to short ion transport length for both electron and zinc ion transport,…”

Reducing Concentration Polarization and Enhancing the Performance of Flexible Nickel‐Zinc Battery Using Polytetrafluoroethylene as Electrode Additive

“…Although PEO is water soluble, it is insoluble in strong alkaline media such as concentrated KOH solution. PTFE is highly hydrophobic, chemically stable, and has been used in rigid batteries including Ni‐Zn,, Li‐O 2 and MnO 2 ‐Zn . In this study, PEO and PTFE were tested and compared as binding additives.…”

“…Furthermore, PTFE does not dissolve in aqueous electrolytes thus avoiding electrode disintegration. These properties make PTFE a potential electrode binder ,. The objective of this research is to develop flexible electrodes by facile mixing of ingredients and study different binders.…”