In Situ Reactive Assembly of Scalable Core–Shell Sulfur–MnO2 Composite Cathodes

详细信息    查看全文

• 作者：Xiao Liang ; Linda F. Nazar
• 刊名：ACS Nano
• 出版年：2016
• 出版时间：April 26, 2016
• 年：2016
• 卷：10
• 期：4
• 页码：4192-4198
• 全文大小：430K
• 年卷期：0
• ISSN：1936-086X

文摘

The lithium–sulfur battery is the subject of much recent attention, but the polysulfide shuttle remains problematic owing to dissolution of intermediate polysulfide species in the electrolyte. Despite much effort in limiting such dissolution via physical confinement or chemical binding to the sulfur host materials, the high cost and complicated preparation of the related materials present an impediment to their practical application. Here we demonstrate a simple methodology to fabricate an effective nanometric MnO₂ shell on sulfur particles, which is realized by an in situ redox reaction between sulfur and KMnO₄ under ambient conditions. The bifunctional MnO₂ shell provides physical confinement and chemical interaction and shows excellent efficiency for trapping the polysulfides. MnO₂ sheets crystallized onto nanosized sulfur particles result in cathodes with a very low fading rate of 0.039% per cycle over 1700 cycles in Li–S cells. Moreover, directly crystallizing nanometric shells of MnO₂ on micrometer-sized sublimed sulfur delivers stable Li–S cycling performance over 800 cycles. Since both sulfur and KMnO₄ are inexpensive and widely used, the production of MnO₂-coated sulfur composites can be easily scaled-up for practical applications of Li–S batteries in light of the very simple reaction processes involved.