Department of Physics, Division of Condensed Matter Physics, Chalmers University of Technology, SE-412 96 Göteborg, Sweden.
Department of Chemistry and Chemical Engineering, Division of Applied Chemistry, Chalmers University of Technology, SE-412 96 Göteborg, Sweden.
Sci Rep. 2016 Dec 23;6:39615. doi: 10.1038/srep39615.
Societies' increasing need for energy storage makes it necessary to explore new concepts beyond the traditional lithium ion battery. A promising candidate is the lithium-sulfur technology with the potential to increase the energy density of the battery by a factor of 3-5. However, so far the many problems with the lithium-sulfur system have not been solved satisfactory. Here we report on a new approach utilizing a self-standing reduced graphene oxide based aerogel directly as electrodes, i.e. without further processing and without the addition of binder or conducting agents. We can thereby disrupt the common paradigm of "no battery without binder" and can pave the way to a lithium-sulfur battery with a high practical energy density. The aerogels are synthesized via a one-pot method and consist of more than 2/3 sulfur, contained inside a porous few-layered reduced graphene oxide matrix. By combining the graphene-based aerogel cathode with an electrolyte and a lithium metal anode, we demonstrate a lithium-sulfur cell with high areal capacity (more than 3 mAh/cm after 75 cycles), excellent capacity retention over 200 cycles and good sulfur utilization. Based on this performance we estimate that the energy density of this concept-cell can significantly exceed the Department of Energy (DEO) 2020-target set for transport applications.
社会对储能的需求不断增加，这使得我们有必要探索超越传统锂离子电池的新概念。一种很有前途的候选技术是锂硫技术，它有可能将电池的能量密度提高 3-5 倍。然而，到目前为止，锂硫系统的许多问题还没有得到满意的解决。在这里，我们报告了一种新的方法，利用自支撑的还原氧化石墨烯基气凝胶直接作为电极，即无需进一步加工，也无需添加粘合剂或导电剂。我们可以打破“没有粘合剂就没有电池”的普遍观念，并为具有高实际能量密度的锂硫电池铺平道路。气凝胶是通过一锅法合成的，由超过 2/3 的硫组成，包含在多孔的少层还原氧化石墨烯基质中。通过将基于石墨烯的气凝胶阴极与电解质和锂金属阳极结合，我们展示了一种具有高面容量（超过 75 次循环后超过 3 mAh/cm2）、200 次循环以上出色的容量保持率和良好的硫利用率的锂硫电池。基于这种性能，我们估计这种概念电池的能量密度可以显著超过美国能源部（DOE）为运输应用设定的 2020 年目标。
