Study On Novel Anodic Materials For Zinc-Nikel Secondary Batteries

ABSTRACT:In recent years, there is an overwhelming need for a reliable, stable and cost effective energy storage device for applications ranging from large-scale energy storage to electric and hybrid vehicle applications. Widely used in the market of the lead-acid battery has serious polluting to the environment. The Zinc-Nikel secondary batteries with an operating voltage of～1.765V and the battery holds an almost constant voltage during most of the discharge period and exhibits voltage stability at different discharge rates. In addition, raw materials of the Zinc-Nikel secondary batteries are in rich and environmental friendly. Therefore, Zinc-Nikel secondary batterry is a promising candidate for the new generation of green power sources used in electric vehicle in recent years. However, the secondary zinc batteries are usually limited in widespread commercialization by the poor cycle life and inferior discharge performance. The failure is usually caused by the drawbacks of zinc electrode, such as zinc dendrite, zinc self-corrosion and shape change in charge-discharge processes. The problems mainly derive from a high solubility of zinc active material in alkaline electrolyte. Hence, many attempts have been made to conquer the problems, most of researchers have focused on the electrolyte, modification of ZnO and additives in the electrodes.Base on these points, the present work discussed the novel alcohol-thermal synthesis method of calcium zincates negative electrode materials for Ni-Zn secondary batteries, the electrochemical properties of Zn-Al-In-LDHs prepared by hrdrothermal methods as novel anodic materials for Zinc-Nikel secondary batteries, A high-rate, high-capacity and superior cycle stability anode materials of ZnAl layered double oxides nanocomposites for Zinc-Nikel secondary batteries.Calcium zincates are synthesized using ZnO and Ca(OH)2in different alcohol solutions by the alcohol-thermal method. Through the scanning electron microscopy (SEM), transmission electron microscope (TEM) and high resolution transmission electron microscope (HRTEM) analysis, the as-prepared samples with small particles are well-crystallized. Additionally, the morphologies of as-prepared calcium zincates are distinct in different reaction solvents such as ethanol, isopropanol and n-butanol, and the calcium zincates synthesized in the ethanol and isopropanol solutions have more excellent crystallinity. As the negative electrode materials for Zinc-Nikel secondary batteries, the electrochemistry properties of calcium zincates are examined by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge-discharge testing techniques. The results imply that calcium zincates synthesized in the ethanol solution have lower polarization and better reversibility. The cycle performance analysis shows the as-prepared calcium zincates have a very greatly improvement in cycle life and discharge capacity compared with other methods. All of the test results show that the calcium zincates synthesized in the ethanol solution exhibit the best electrochemical performances.Zn-Al-In layered double hydroxides (LDHs) are synthesized by hydrothermal method and investigated as negative electrode materials for Zinc-Nikel secondary batteries. The Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images show the as-prepared samples are well-crystallized and hexagon structure. The electrochemical performances of Zn-Al-LDHs and Zn-Al-In-LDHs with different Zn/Al/In molar ration are investigated by the cyclic voltammograms (CV), Tafel polarization and galvanostatic charge-discharge measurements. Zn-Al-LDHs shows good stability in the first300-cycles. However, during the subsequent cycles, the discharge capacity decreases with increasing of the cycles. Compared with Zn-Al-LDHs, Zn-Al-In-LDHs with different Zn/Al/In molar rations, especially the sample of Zn/Al/In=3:0.75:0.25(molar ration) have higher discharge capacity and more stable cycling performances. This battery can undergo at least800charge-discharge cycles at constant current of1C without dendrite and short circuits. The discharge capacity of Zn-Al-In-LDHs after the800th cycle remains about380mAh g-1. Zn-Al-In-LDHs possess a high rate capabiliy to meet the needs of high-storage applications.In the present work, Zn-Al layered double hydroxides (Zn-Al-LDH) were prepared by hydrothermal method, and their corresponding calcinated product (ZnAl layered double oxides) was calcined in atmosphere of air at600℃for6h from Zn-Al layered double hydroxides. The characterization of precursors and their corresponding calcinated products (ZnAl layered double oxides) were carried out by Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM) and EDS. The results show that the as-prepared samples are well-crystallized and hexagon structure. The electrochemical performances of Zn-Al-LDH and Zn-Al-LDO are investigated by the cyclic voltammograms (CV), Tafel polarization and galvanostatic charge-discharge measurements. Zn-Al-LDH shows good stability in the first300-cycles. However, during the subsequent cycles, the discharge capacity decreases with increasing of the cycles. Compared with Zn-Al-LDH, Zn-Al-LDO possess higher discharge capacity, better stability and longer cycle life. The discharge capacity of Zn-Al-LDO remains about487mAh g-1after the1000th cycle. Zn-Al-LDO possess a high rate capability to meet the needs of high-storage applications.