Pomegranate‐Structured Silica/Sulfur Composite Cathodes for High‐Performance Lithium–Sulfur Batteries |
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Authors: | Dr Sinho Choi Dr Dawei Su Myoungsoo Shin Prof Soojin Park Prof Guoxiu Wang |
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Institution: | 1. Centre for Clean Energy Technology, Faculty of Science, University of Technology Sydney, NSW, Australia;2. Department of Energy Engineering, School of Energy and Chemical Engineering, UNIST, Ulsan, Republic of Korea. |
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Abstract: | Porous materials have many structural advantages for energy storage and conversion devices such as rechargeable batteries, supercapacitors, and fuel cells. When applied as a host material in lithium‐sulfur batteries, porous silica materials with a pomegranate‐like architecture can not only act as a buffer matrix for accommodating a large volume change of sulfur, but also suppress the polysulfide shuttle effect. The porous silica/sulfur composite cathodes exhibit excellent electrochemical performances including a high specific capacity of 1450 mA h g?1, a reversible capacity of 82.9 % after 100 cycles at a rate of C/2 (1 C=1672 mA g?1) and an extended cyclability over 300 cycles at 1 C‐rate. Furthermore, the high polysulfide adsorption property of porous silica has been proven by ex‐situ analyses, showing a relationship between the surface area of silica and polysulfide adsorption ability. In particular, the modified porous silica/sulfur composite cathode, which is treated by a deep‐lithiation process in the first discharge step, exhibits a highly reversible capacity of 94.5 % at 1C‐rate after 300 cycles owing to a formation of lithiated‐silica frames and stable solid‐electrolyte‐interphase layers. |
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Keywords: | lithium-sulfur batteries polysulfide adsorption porous silica solid electrolyte interphase sulfur composite cathodes |
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