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Chen S, Peng C, Xue D, Ma L, Zhi C. Alkaline Tolerant Antifreezing Additive Enabling Aqueous Zn||Ni Battery Operating at −60 °C. Angew Chem Int Ed Engl 2022; 61:e202212767. [DOI: 10.1002/anie.202212767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Indexed: 11/07/2022]
Affiliation(s)
- Shengmei Chen
- Department of Materials Science and Engineering City University of Hong Kong 83 Tat Chee Avenue Kowloon, Hong Kong 999077 P. R. China
| | - Chao Peng
- Multiscale Crystal Materials Research Center Shenzhen Institute of Advanced Technology Chinese Academy of Sciences Shenzhen 518055 China
| | - Dongfeng Xue
- Multiscale Crystal Materials Research Center Shenzhen Institute of Advanced Technology Chinese Academy of Sciences Shenzhen 518055 China
| | - Longtao Ma
- Frontiers Science Center for Flexible Electronics Institute of Flexible Electronics Northwestern Polytechnical University Xi'an 710072 P. R. China
| | - Chunyi Zhi
- Department of Materials Science and Engineering City University of Hong Kong 83 Tat Chee Avenue Kowloon, Hong Kong 999077 P. R. China
- Center for Advanced Nuclear Safety and Sustainable Development City University of Hong Kong Kowloon, Hong Kong 999077 P. R. China
- Hong Kong Institute for Clean Energy City University of Hong Kong Kowloon, Hong Kong 999077 Hong Kong
- Centre for Functional Photonics City University of Hong Kong Kowloon, Hong Kong Hong Kong
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Abstract
ZnO has many technological applications which largely depend on its properties, which can be tuned by controlled synthesis. Ideally, the most convenient ZnO synthesis is carried out at room temperature in an aqueous solvent. However, the correct temperature values are often loosely defined. In the current paper, we performed the synthesis of ZnO in an aqueous solvent by varying the reaction and drying temperatures by 10 °C steps, and we monitored the synthesis products primarily by XRD). We found out that a simple direct synthesis of ZnO, without additional surfactant, pumping, or freezing, required both a reaction (TP) and a drying (TD) temperature of 40 °C. Higher temperatures also afforded ZnO, but lowering any of the TP or TD below the threshold value resulted either in the achievement of Zn(OH)2 or a mixture of Zn(OH)2/ZnO. A more detailed Rietveld analysis of the ZnO samples revealed a density variation of about 4% (5.44 to 5.68 gcm−3) with the synthesis temperature, and an increase of the nanoparticles’ average size, which was also verified by SEM images. The average size of the ZnO synthesized at TP = TD = 40 °C was 42 nm, as estimated by XRD, and 53 ± 10 nm, as estimated by SEM. For higher synthesis temperatures, they vary between 76 nm and 71 nm (XRD estimate) or 65 ± 12 nm and 69 ± 11 nm (SEM estimate) for TP = 50 °C, TD = 40 °C, or TP = TD = 60 °C, respectively. At TP = TD = 30 °C, micrometric structures aggregated in foils are obtained, which segregate nanoparticles of ZnO if TD is raised to 40 °C. The optical properties of ZnO obtained by UV-Vis reflectance spectroscopy indicate a red shift of the band gap by ~0.1 eV.
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