Fan Lei, Zhuang Houlong L, Zhang Kaihang, Cooper Valentino R, Li Qi, Lu Yingying
State Key Laboratory of Chemical Engineering Institute of Pharmaceutical Engineering College of Chemical and Biological Engineering Zhejiang University Hangzhou 310027 China.
Department of Mechanical and Aerospace Engineering Princeton University NJ 08544 USA.
Adv Sci (Weinh). 2016 Jul 21;3(12):1600175. doi: 10.1002/advs.201600175. eCollection 2016 Dec.
Lithium-sulfur (Li-S) battery is one of the most promising alternatives for the current state-of-the-art lithium-ion batteries due to its high theoretical energy density and low production cost from the use of sulfur. However, the commercialization of Li-S batteries has been so far limited to the cyclability and the retention of active sulfur materials. Using co-electrospinning and physical vapor deposition procedures, we created a class of chloride-carbon nanofiber composites, and studied their effectiveness on polysulfides sequestration. By trapping sulfur reduction products in the modified cathode through both chemical and physical confinements, these chloride-coated cathodes are shown to remarkably suppress the polysulfide dissolution and shuttling between lithium and sulfur electrodes. From adsorption experiments and theoretical calculations, it is shown that not only the sulfide-adsorption effect but also the diffusivity in the vicinity of these chlorides materials plays an important role on the reversibility of sulfur-based cathode upon repeated cycles. Balancing the adsorption and diffusion effects of these nonconductive materials could lead to the enhanced cycling performance of an Li-S cell. Electrochemical analyses over hundreds of cycles indicate that cells containing indium chloride-modified carbon nanofiber outperform cells with other halogenated salts, delivering an average specific capacity of above 1200 mAh g at 0.2 C.
锂硫（Li-S）电池因其高理论能量密度以及使用硫带来的低成本，成为当前最先进锂离子电池最具前景的替代方案之一。然而，迄今为止，Li-S电池的商业化受到循环稳定性和活性硫材料保留率的限制。通过共电纺丝和物理气相沉积工艺，我们制备了一类氯化物-碳纳米纤维复合材料，并研究了它们对多硫化物的封存效果。通过化学和物理限制将硫还原产物捕获在改性阴极中，这些涂覆氯化物的阴极可显著抑制多硫化物在锂电极和硫电极之间的溶解和穿梭。吸附实验和理论计算表明，不仅硫化物吸附效应，而且这些氯化物材料附近的扩散率对基于硫的阴极在反复循环时的可逆性也起着重要作用。平衡这些非导电材料的吸附和扩散效应可提高Li-S电池的循环性能。数百次循环的电化学分析表明，含氯化铟改性碳纳米纤维的电池性能优于含其他卤化盐的电池，在0.2 C下平均比容量高于1200 mAh g。
