The Electrochemistry with Lithium versus Sodium of Selenium Confined To Slit Micropores in Carbon.

Xin, Sen; Yu, Le; You, Ya; Cong, Huai-Ping; Yin, Ya-Xia; Du, Xue-Li; Guo, Yu-Guo; Yu, Shu-Hong et al. · Nano Lett · 2016

basic_science · Level V

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Abstract

Substitution of selenium for sulfur in the cathode of a rechargeable battery containing Sx molecules in microporous slits in carbon allows a better characterization of the electrochemical reactions that occur. Paired with a metallic lithium anode, the Sex chains are converted to Li2Se in a single-step reaction. With a sodium anode, a sequential chemical reaction is characterized by a continuous chain shortening of Sex upon initial discharge before completing the reduction to Na2Se; on charge, the reconstituted Sex molecules retain a smaller x value than the original Sex chain molecule. In both cases, the Se molecules remain almost completely confined to the micropore slits to give a long cycle life.