دانلود مقاله ترجمه شده کارایی الکتروشیمیایی الکترود فیبر کربن با روکش قلع – مجله الزویر

فهرست مطالب:

چکیده
مقدمه
آزمایش
ساخت و تعیین خصوصیات الکترودها
نتایج و بحث
ریزساختار الکترودهای تولید شده
عملکرد الکتروشیمیایی
ارزیابی میکروسکوپی تجزیه الکتروشیمیایی
نتیجه گیری

بخشی از ترجمه:

 پوشش استرانسیم با ذرات بسیار ریز با ضخامت ۰٫۵ میکرومتر روی فیبرهای با جهات تصادفی کاغذ کربن فیبری رسوب داده شد. این کار برای تولید اند کامپوزیت فیبری کربن استرانسیم برای باطری های قابل شارژ انجام شد. تست های تخلیه شارژ گالوانواستاتیک با ترکم جریان نسبتا بالا نشان دادند که الکترود Sn–CF دارای ظرفیت برگشت پذیر ۱٫۹۶ میلی آمپر با نگهداشت ۵۰% در مقایسه با ۲۳ درصد در پوشش استرانسیم روسوب یافته روی فویل می می باشد. ظرفیت نگه داشت بالا در الکترود Sn–CFP، به دلایل ذیل بود.
ضخامت اندک و سطح ویژه زیاد پوشش استرانسیم روی فیبر کربن ناشی از افزایش واکنش شیمیایی و مقاومت به تغییر جریان علاوه بر ایفای نقش کلکتورهای جریان جهت دار، فیبرهای کربن در فرایند های لیتیم دار کردن و لیتیم زدایی به عنوان مواد فعال نقش دارند که موجب بهبود عملکرد کل سلول و پایداری ان می شود.

بخشی از مقاله انگلیسی:

۱٫ Introduction The most common anode material used in Li-ion batteries is graphite, due to its low cost, availability and durability [1,2]. In graphitic anodes, the Li+ insertion mechanism corresponds to the reversible, progressive intercalation of Li+ ions between graphene layers to reach a theoretical capacity of 372 mAh g−۱ if LiC6 is formed [3], compared to a practical capacity of 350 mAh g−۱ [۴]. Recent years have seen a growing interest in the use of affordably mass-producible metals (e.g., Si, Sn, Sb, In, Bi, Al) as Li-ion battery anode materials to achieve a higher capacity and a more positive lithiation voltage vs. Li/Li+, minimizing the risk of Li plating that is a safety problem with carbonaceous anodes [4,5]. However, using the aforementionedmetals as anodes for Li-ion batteries produces large volume changes during lithiation/delithiation processes. Thus, in order to improve durability while maintaining high capacity, new strategies have been implemented to prevent the adverse effects of large volume changes. One strategy is the development of intermetallic anode materials by alloying active elements with inactive elements (e.g., Cu6Sn5, Cu2Sb) to compensate for the expansion of the active materials [6,7]. Another strategy employed by some researchers is the development of composite anode materials by mixing active elements with carbonaceous materials (e.g., Si–C, Sn–C) [8,9] or oxides (e.g., Sb–VO4, Sb–Mn2O7, Sn–Al2O3) [10,11]. For example, Magasinski et al. [8] used a CVD technique to produce Si–C nanocomposite granules containing 50 wt% Si nanoparticles, and reported a capacity of 1500 mAh g−۱ with an efficiency of about 90% for 100 cycles. A third strategy involves the design and development of anode materials with micro- and nano-scale surface textures that provide a large surface-to-volume ratio. This may result in an improvement ofthe electrical contact between the active material and the current collector, an enhancement of the chemical reactivity of the active material to the electrolyte, and an increase in the tolerance for the volume change [8,12,13]. Among the alternative anode materials that have been studied, Sn is particularly important because of its high theoretical capacity of 992 mAh g−۱ (i.e., if Li4.4Sn is reached) [14–۱۷]. The Li+ insertion mechanism in Sn-based anodes corresponds to the formation of Li–Sn intermetallics according to: xLi+ + xe− + Sn ↔ LixSn (0 < x < 4.4) (1) Sn has a poor capacity retention, however, due to its large volume change (up to 300%) during charge–discharge cycles, which causes the pulverization of the electrode after only a few cycles [14–۱۷]. In order to improve the cycling performance of Sn anodes, Sn-based intermetallic compounds and composite materials have been developed. Intermetallics formed of Sn and inactive elements, such as Cu6Sn5 [18–۲۰], CoSn3 [21] and Ni3Sn4 [22–۲۴], have a lower specific capacity than pure Sn, but their capacity retention is significantly higher. There are also several examples of Sn-based composite anodes in the literature. Noh et al.[25] produced amorphous carbon-coated Sn particles composed of 80 wt% Sn. Testing a composite electrode with 60 wt% particles,they measured a capacity of 680 mAh g−۱ and a capacity retention of 98% after 50 cycles. Park et al. [26] showed that the cycling performance of electrodeposited Sn coatings could be improved by dispersing 16 vol% acetylene black particles with a size smaller than40 minto the Snmatrix. They reported a capacity of 460 mAh g−۱ and a capacity retention of 43% after twenty cycles for the composite electrode, whereas a similar 10 m-thick Sn coating showed a small capacity of only 20 mAh g−۱ from the beginning. This improvement in the cycling performance was attributed to the buffering effect that the acetylene black particles had on the volume change. On the other hand, the use of three-dimensional substrates (current collectors) for Sn-based coatings like metallic foams [27–۲۹],nanopillar-textured Cu surface [30] and carbonfibre paper (CFP) [31], have also shown to improve the durability of the anode electrodes. Among these, using CFP seems to be the simplest, most cost-effective approach, because it does not require adding extra steps to the electrode production route. The aim of this study was to fabricate an Sn–carbon fibre composite as an alternative (with higher capacity and improved safety) to commercial graphitic anodes for rechargeable Li-ion batteries using a cost-effective electrodeposition process. Galvanostatic charge–discharge cycling tests would then be conducted to evaluate the electrode’s reversible capacity and cycling performance with the goal of understanding the roles that Sn and carbon fibres play in the overall performance of these composite anodes. Furthermore, the microstructures of the electrodes were studied to understand the electrochemical degradation mechanisms and suggest possible materials processing solutions that mightimprove the performance of the composite electrodes.To fabricate the composite electrode, a thin film of ultrafine grain Sn (it has been suggested that a reduction in the active material’s grain size may benefitthe cycling performance by reducing crack size and delamination from the current collector during charge–discharge cycles [14]) was electrodeposited on a CFP sheet with randomly oriented carbon fibres. CFP is low-cost and commercially available, and it has a large surface area and good electrical conductivity. The electrochemical performance and the degradation mechanisms of this electrode were compared to an Sn coating electrodeposited on a Cu foil.

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