Electrochemical behavior of zinc particles with silica based coatings as anode material for zinc air batteries with improved discharge capacity
| Autor: | Manuela Schmid, Monika Willert-Porada |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Materials science
Aqueous solution Passivation Renewable Energy Sustainability and the Environment Galvanic anode Precipitation (chemistry) Inorganic chemistry Energy Engineering and Power Technology chemistry.chemical_element 02 engineering and technology Zinc 010402 general chemistry 021001 nanoscience & nanotechnology Electrochemistry 01 natural sciences 0104 chemical sciences Anode chemistry Electrical and Electronic Engineering Physical and Theoretical Chemistry 0210 nano-technology Dissolution |
| Zdroj: | Journal of Power Sources. 351:115-122 |
| ISSN: | 0378-7753 |
| DOI: | 10.1016/j.jpowsour.2017.03.096 |
| Popis: | Silica coatings on zinc particles as anode material for alkaline zinc air batteries are expected to reduce early formation of irreversible ZnO passivation layers during discharge by controlling zinc dissolution and precipitation of supersaturated zincates, Zn(OH)42-. Zinc particles were coated with SiO2 (thickness: 15 nm) by chemical solution deposition and with Zn2SiO4 (thickness: 20 nm) by chemical vapor deposition. These coatings formed a Si(OH)4 gel in aqueous KOH and retarded hydrogen evolution by 40%. By treatment in aqueous KOH and drying afterwards, the silica coatings were changed into ZnO-K2O·SiO2 layers. In this work, the electrochemical performance of such coated zinc particles is investigated by different electrochemical methods in order to gain a deeper understanding of the mechanisms of the coatings, which reduce zinc passivation. In particular, zinc utilization and changes in internal resistance are investigated. Moreover, methods for determination of diffusion coefficients, charge carrier numbers and activation energies for electrochemical oxidation are determined. SiO2-coated zinc particles show improved discharge capacity (CVD-coated zinc: 69% zinc utilization, CSD-coated zinc: 62% zinc utilization) as compared to as-received zinc (57% zinc utilization) at C/20 rate, by reducing supersaturation of zincates. Additionally, KOH-modified SiO2-coated zinc particles enhance rechargeability after 100% depth-of-discharge. |
| Databáze: | OpenAIRE |
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