含稀土钇电极材料的声化学制备及电化学性能

通过超声浸渍法以不同浓度的Y(NO3)3溶液成功地制得几种声化学改性锌粉, 以期改善碱性电池锌电极的电化学性能. 利用扫描电镜(SEM)、X射线衍射(XRD)及电化学测试等方法考察了改性锌粉上Y(OH)3/Y2O3的形成及相应锌电极的耐腐蚀和循环性能. 结果表明, Y(NO3)3浓度为0.036 mol·L-1时, 声化学改性锌粉表面均匀分布着颗粒状的Y(OH)3/Y2O3, 且这些钇化合物优先生长在锌粉表面的缺陷位置, 阻挡了电化学过程中锌酸根离子向碱性电解液中的溶解与扩散, 使得相应锌电极的缓蚀效率达79.6%, 且20次循环伏安曲线的阴、阳极峰电位差比空白样减小了285 mV. 将这种改性锌粉和空白锌粉组装成模拟锌银电池, 在250 mA·cm-2的高放电电流密度下测试发现, 声化学改性锌粉的锌电极从1次到30次循环的放电容量损失仅为62.7 mAh·g-1; 且放电容量在50周期时达到322.6 mAh·g-1, 说明声化学改性锌粉可明显提高电极的放电容量和循环寿命.

Sonochemical Fabrication and Electrochemical Performance of Electrode Materials Containing Rare Earth Yttrium

In order to improve the electrochemical performance of zinc electrodes in alkaline batteries, several sonochemically modified zinc powders were successfully prepared in different concentrations of Y(NO3)3 solutions by means of ultrasonic immersion. Moreover, the formation of Y(OH)3/Y2O3 on modified zinc powder, the corrosion inhibition and cyclic performance of corresponding zinc electrodes were investigated through scanning electron microscopy (SEM), X-ray diffraction (XRD), electrochemical and other techniques. The results showed that Y(OH)3/Y2O3 particles were uniformly distributed on sonochemically modified zinc powder with 0.036 mol·L-1 Y(NO3)3 solution. Simultaneously, the yttrium compounds grew preferentially on the defect sites of zinc powder surface, and prevented the dissolution and diffusion of zincate anions into alkaline electrolyte during the electrochemical process. All these results contributed to the facts that the inhibition efficiency of zinc electrode achieved 79.6%, and differential value between anodic and cathodic peak potentials decreased by 285 mV at the 20th cyclic voltammogram. Simulated silver-zinc batteries were assembled using bare zinc powder and the zinc powder modified with 0.036 mol·L-1 Y(NO3)3 solution. According to the detections of the batteries at a high discharge current density of 250 mA·cm-2, capacity loss of zinc electrode containing the modified zinc powder reached only 62.7 mAh·g-1 from the 1st to 30th cycles, and discharge capacity of 322.6 mAh·g -1 was still reserved after 50 cycles. Therefore, a conclusion was drawn that discharge capacity and cycle life of zinc electrodes were obviously enhanced owing to the application of sonochemically modified zinc powder.