Experimental Studies of Carbon Electrodes With Various Surface Area for Li–O2 Batteries
Experimental Studies of Carbon Electrodes With Various Surface Area for Li–O2 Batteries
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DOI：
10.1115/1.4043229
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发表时间：
2019-11
影响因子：
2.5
通讯作者：
Fangzhou Wang;P. Kahol;R. Gupta;Xianglin Li
中科院分区：
文献类型：
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作者：
Fangzhou Wang;P. Kahol;R. Gupta;Xianglin Li
本文研究了由三种商用炭和由废茶叶制成的炭制成的碳电极的Li−O2电池。废茶叶从家用茶叶中回收，并使用KOH活化。碳材料具有不同的比表面积，多孔结构以N2吸附/脱附为特征。Vulcan XC 72碳显示出比乙炔黑（76.5 m2/g）和Super P（60.9 m2/g）更高的比表面积（264.1 m2/g）。活化后的茶叶具有2868.4m2/g的极高比表面积。首先，我们发现商业碳在0.5 mA/cm 2下实现了约2.50 Ah/g的类似放电容量。碳材料中的微孔具有高比表面积，但无法容纳固体放电产物（Li 2 O2），因此无助于实现更高的放电容量。乙炔黑和Vulcan XC 72的混合由于优化的多孔结构而提高了放电容量。当Vulcan XC 72的质量分数从0变化到0.3时，在0.5 mA/cm 2下的放电容量增加了42%（从2.73 ± 0.46增加到3.88 ± 0.22 Ah/g）。其次，由活化茶叶制成的电极首次在Li-O2电池中得到展示。活性茶叶和乙炔黑的混合物证实了具有不同比表面积的碳材料的混合物可以提高放电容量。此外，由回收茶叶制成的碳可以降低电极的成本，使电极更经济。这项研究实际上提高了使用混合碳的Li−O2电池的放电容量，并提供了一种成本更低、环境友好性更好的碳电极制造方法。
Li−O2 batteries with carbon electrodes made from three commercial carbons and carbon made from waste tea leaves are investigated in this study. The waste tea leaves are recycled from household tea leaves and activated using KOH. The carbon materials have various specific surface areas, and porous structures are characterized by the N2 adsorption/desorption. Vulcan XC 72 carbon shows a higher specific surface area (264.1 m2/g) than the acetylene black (76.5 m2/g) and Super P (60.9 m2/g). The activated tea leaves have an extremely high specific surface area of 2868.4 m2/g. First, we find that the commercial carbons achieve similar discharge capacities of ∼2.50 Ah/g at 0.5 mA/cm2. The micropores in carbon materials result in a high specific surface area but cannot help to achieve higher discharge capacity because it cannot accommodate the solid discharge product (Li2O2). Mixing the acetylene black and the Vulcan XC 72 improves the discharge capacity due to the optimized porous structure. The discharge capacity increases by 42% (from 2.73 ± 0.46 to 3.88 ± 0.22 Ah/g) at 0.5 mA/cm2 when the mass fraction of Vulcan XC 72 changes from 0 to 0.3. Second, the electrode made from activated tea leaves is demonstrated for the first time in Li−O2 batteries. Mixtures of activated tea leaves and acetylene black confirm that mixtures of carbon material with different specific surface areas can increase the discharge capacity. Moreover, carbon made from recycled tea leaves can reduce the cost of the electrode, making electrodes more economically achievable. This study practically enhances the discharge capacity of Li−O2 batteries using mixed carbons and provides a method for fabricating carbon electrodes with lower cost and better environmental friendliness.