Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China.
Tsinghua-Berkeley Shenzhen Institute, Tsinghua University, Shenzhen 518055, China.
Nat Commun. 2017 Mar 3;8:14627. doi: 10.1038/ncomms14627.
Although the rechargeable lithium-sulfur battery is an advanced energy storage system, its practical implementation has been impeded by many issues, in particular the shuttle effect causing rapid capacity fade and low Coulombic efficiency. Herein, we report a conductive porous vanadium nitride nanoribbon/graphene composite accommodating the catholyte as the cathode of a lithium-sulfur battery. The vanadium nitride/graphene composite provides strong anchoring for polysulfides and fast polysulfide conversion. The anchoring effect of vanadium nitride is confirmed by experimental and theoretical results. Owing to the high conductivity of vanadium nitride, the composite cathode exhibits lower polarization and faster redox reaction kinetics than a reduced graphene oxide cathode, showing good rate and cycling performances. The initial capacity reaches 1,471 mAh g and the capacity after 100 cycles is 1,252 mAh g at 0.2 C, a loss of only 15%, offering a potential for use in high energy lithium-sulfur batteries.
尽管可充电锂硫电池是一种先进的储能系统，但由于许多问题的存在，其实际应用受到了阻碍，特别是穿梭效应导致的容量快速衰减和低库仑效率。在此，我们报告了一种作为锂硫电池正极的导电多孔氮化钒纳米带/石墨烯复合材料，该复合材料可以容纳电解质。氮化钒/石墨烯复合材料为多硫化物提供了强大的锚定位点，并促进了多硫化物的快速转化。氮化钒的锚定作用通过实验和理论结果得到了证实。由于氮化钒的高导电性，与还原氧化石墨烯正极相比，复合正极具有更低的极化和更快的氧化还原反应动力学，表现出良好的倍率和循环性能。在 0.2C 时，初始容量达到 1471 mAh g，经过 100 次循环后，容量为 1252 mAh g，仅损失 15%，为高能量锂硫电池的应用提供了潜力。
