{"id":5456,"date":"2020-07-30T17:07:48","date_gmt":"2020-07-30T08:07:48","guid":{"rendered":"https:\/\/www.waseda.jp\/fsci\/wise\/?p=5456"},"modified":"2021-04-12T09:44:03","modified_gmt":"2021-04-12T00:44:03","slug":"%e3%82%ab%e3%83%bc%e3%83%9c%e3%83%b3%e3%83%8a%e3%83%8e%e3%83%81%e3%83%a5%e3%83%bc%e3%83%96%e3%81%ae%e3%83%aa%e3%83%81%e3%82%a6%e3%83%a0%e3%82%a4%e3%82%aa%e3%83%b3%e9%9b%bb%e6%b1%a0%e3%81%ae%e9%9b%bb-5","status":"publish","type":"post","link":"https:\/\/www.waseda.jp\/fsci\/wise\/prj\/2020\/07\/30\/5456\/","title":{"rendered":"\u9577\u5c3a\u30ab\u30fc\u30dc\u30f3\u30ca\u30ce\u30c1\u30e5\u30fc\u30d6\u306e\u5408\u6210\u3068\u30ea\u30c1\u30a6\u30e0-\u786b\u9ec4\u96fb\u6c60\u3078\u306e\u5fdc\u7528"},"content":{"rendered":"

Lithium-sulfur (Li-S) batteries are one of\u00a0<\/span>the\u00a0<\/span>most promising candidates for next-generation\u00a0<\/span>energy-storage systems<\/span>\u00a0beyond routine lithium-ion batteries due to their high energy densities<\/span>, low cost and natural abundance of\u00a0<\/span>sulfur<\/span>. Their extreme<\/span>ly<\/span>\u00a0high gravimetric energy density\u00a0<\/span>owing to the huge\u00a0<\/span>theoretical specific capacit<\/span>ies of cathode<\/span>\u00a0and anode and cost-effectiveness of sulfur provide them huge potentials to satisfy the increasing demands of energy storage technologies, especially for electric vehicles (EVs), hybrid EVs and stationary energy storage systems. In spite of these advantages, the practical applications of Li-S batteries are impeded by several challenges, such as low sulfur utilization, fast capacity fade and capacity loss, which\u00a0<\/span>mainly originate from<\/span>\u00a0the low conductivity of sulfur and its end-discharge product Li<\/span>2<\/span>S, shuttling effect of the soluble\u00a0<\/span>poly<\/span>sulfide intermediates and large volume changes.\u00a0<\/span>\u00a0<\/span><\/p>\n

Among numerous<\/span>\u00a0efforts have been devoted to address these unsolved issues, carbon nanotubes\u00a0<\/span>(CNTs)\u00a0<\/span>have shown promising results when hybridized with sulfur to fabricate composite cathodes.<\/span>\u00a0Peng et al. improved the cycling stability of high-sulfur-loading Li-S batteries by applying 3D CNT current collectors.<\/span>[<\/span>1]<\/span>\u00a0<\/span>S<\/span>ulfur-carbon composite cathode with high areal capacities was also produced by vapor-phase filtration of sulfur onto CNT foams.<\/span>[2]<\/span>\u00a0These works show the effectiveness of CNTs, however, they<\/span>\u00a0<\/span>overlook the critical parameters, including\u00a0<\/span>low\u00a0<\/span>sulfur loading, small sulfur content, and impractically high\u00a0<\/span>electrolyte\/sulfur ratio. With these conditions, it is easy to achieve good electrode-based performance,\u00a0<\/span>while<\/span>\u00a0it results in impractically small cell-based performance due to the small fraction of S in the full cell.<\/span>\u00a0<\/span><\/p>\n

In this research, the main purpose is to\u00a0<\/span>synthesis long CNTs with controlled wall number and use them to\u00a0<\/span>fabricate hybridized sulfur and\u00a0<\/span>CNT<\/span>\u00a0<\/span>(<\/span>S-<\/span>CNT)\u00a0<\/span>composite cathodes, which minimize the content of inactive materials without using any current collector and polymeric binder and maximize\u00a0<\/span>S<\/span>\u00a0content<\/span>\u00a0(Fig 1)<\/span>.\u00a0<\/span>\u00a0<\/span><\/p>\n

The\u00a0<\/span>systhesis<\/span>\u00a0of CNTs will be carried out in fluidized-bed CVD method\u00a0<\/span>that\u00a0<\/span>developed by our group previously.\u00a0<\/span>S-CNT cathodes will be fabricated\u00a0<\/span>by facile filtration, melt-diffusion and evaporation\u00a0<\/span>process<\/span>.<\/span>\u00a0<\/span>T<\/span>heir electrochemical performance will be enhanced by examining a series of CNTs of different types for the 3D current collector which captures and activates sulfur inside the sponge-like, free-standing CNT papers.\u00a0<\/span>By analyzing the structure and electrochemical performance of the cathodes, the mechanism of\u00a0<\/span>improved electrochemical performance of Li-S batteries will be\u00a0<\/span>clarified<\/span>.<\/span>\u00a0<\/span><\/p>\n

\"\"<\/p>\n

Fig 1. Different structures between traditional Li-S batteries cathodes and S-CNT cathodes. Advantages of S<\/span>-CNT cathodes are: (1). Eli<\/span>mination of heavy metal current\u00a0<\/span>collectors<\/span>\u00a0and replace them with CNTs; (2). Without using polymeric binders and conductive materials; (3) Inhibit the shuttle effect of\u00a0<\/span>polysulfide and<\/span>\u00a0<\/span>activates sulfur<\/span>.<\/span>\u00a0<\/span><\/p>\n

\u00a0<\/span>[1]<\/span>\u00a0<\/span>H. J. Peng, W. T. Xu, L. Zhu, et al., Adv. Funct. Mater.\u00a0<\/span>26<\/span><\/b>, 35(2016).<\/span>
\n<\/span>[2] M. Li, R. Carter, A. Douglas, et al., ACS Nano\u00a0<\/span>11<\/span><\/b>, 5(2017).<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

Lithium-sulfur (Li-S) batteries are one of\u00a0the\u00a0most promising candidates for next-generation\u00a0energy-storage sy […]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[109],"tags":[],"class_list":["post-5456","post","type-post","status-publish","format-standard","hentry","category-prj","lang-ja","sr-science"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.waseda.jp\/fsci\/wise\/wp-json\/wp\/v2\/posts\/5456","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.waseda.jp\/fsci\/wise\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.waseda.jp\/fsci\/wise\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.waseda.jp\/fsci\/wise\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.waseda.jp\/fsci\/wise\/wp-json\/wp\/v2\/comments?post=5456"}],"version-history":[{"count":6,"href":"https:\/\/www.waseda.jp\/fsci\/wise\/wp-json\/wp\/v2\/posts\/5456\/revisions"}],"predecessor-version":[{"id":6225,"href":"https:\/\/www.waseda.jp\/fsci\/wise\/wp-json\/wp\/v2\/posts\/5456\/revisions\/6225"}],"wp:attachment":[{"href":"https:\/\/www.waseda.jp\/fsci\/wise\/wp-json\/wp\/v2\/media?parent=5456"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.waseda.jp\/fsci\/wise\/wp-json\/wp\/v2\/categories?post=5456"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.waseda.jp\/fsci\/wise\/wp-json\/wp\/v2\/tags?post=5456"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}