Enhanced performance of Li-O₂ battery based on CF_x/C composites as cathode materials

详细信息    查看全文

• 作者：Chaolumen Wu ; Haibin Wang ; Chenbo Liao ; Jun Yang ; ^{yangj723@sjtu.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Lei Li ; ^{lilei0323@sjtu.edu.cn" class="auth_mail" title="E-mail the corresponding author}
• 关键词：lithium-O2 battery ; fluorinated carbon ; air-electrode ; rate capability
• 刊名：Electrochimica Acta
• 出版年：2015
• 出版时间：20 December 2015
• 年：2015
• 卷：186
• 期：Complete
• 页码：631-641
• 全文大小：3278 K

文摘

A hybrid air-electrode composed of a mixture of fluorinated carbon (CF_x) and Ketjen black (KB) active carbon composite materials was prepared to improve performance of Li-O₂ battery. In the hybrid air-electrodes, four kinds of CF_x materials including fluorinated graphite, fluorinated carbon fiber, fluorinated coke and fluorinated black carbon were utilized as lithium insertion materials. The physical properties and morphologies of the KB and CF_x carbon materials were characterized by Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Scanning electron microscopy (SEM) measurements. Compared with the conventional KB air-electrode, all the CF_x/KB hybrid air-electrodes in Li-O₂ batteries showed higher specific discharge capacity, especially at high current density. Among these CF_x/KB hybrid air-electrodes, the fluorinated graphite based electrode showed the best electrochemical performance in Li-O₂ battery due to its highest discharge capacity of the fluorinated graphite material in the Li/CF_x primary battery, highest specific surface area, and highest total pore volume. The electrochemical performance of Li-O₂ and Li-air batteries using the hybrid air-electrodes with the different fluorinated graphite: KB weight ratio, including specific charge and discharge capacity, cycling stability and rate capability were systematically investigated. At a current density of 0.5 mA cm⁻², the fluorinated graphite based air-electrode delivered a high specific discharge capacity of 1138 mAh g⁻¹ in Li-O₂ batteries, which was more than four times than that of the conventional KB air-electrode (265 mAh g⁻¹) under same testing conditions. The battery assembled with the fluorinated graphite based air-electrode exhibited better cycling stability than that of the battery assembled with the conventional KB air-electrode.