Effect of La Addition on the Electrochemical Properties of Secondary Zinc Electrodes

The electrochemical properties of secondary zinc electrodes after La addition by the solid-phase diffusion method have been investigated. The results showed that the La addition to the zinc electrode significantly improved the cycle life. After 80 cycles at 100 mA/g the zinc electrode with 0.5 atom % La addition showed the best cyclic behavior. Its discharge capacity was more than 520 mAh/g. The linear potentiodynamic polarization results showed that suitable La addition significantly suppressed the corrosion behavior of secondary zinc electrodes while little effect on the anodic behavior was found. The potentiostatic polarization results at −100 mV overpotential showed that the growth of zinc dendrites was effectively inhibited by the La addition. Scanning electron microscopy images showed that La addition changed the formation of zinc deposition. X-ray photoelectron spectroscopy results revealed that lanthanum oxides were formed and enriched on the surface during cycling, which prevented the discharge products of zinc electrodes from dissolving in the alkaline electrolyte and suppressed the dendrite growth during charge. © 2004 The Electrochemical Society. All rights reserved.