Anchoring RuO${}_2$ nanoparticles on ultrathin porous carbon shell toward high performance lithium‐sulfur batteries

Despite the high theoretical specific capacity and energy density, the practical application of lithium‐sulfur (Li−S) battery is still hampered by the shuttle of lithium polysulfides and sluggish kinetics of cathode, which results in the loss of active materials and rapid capacity decay of the sulfur cathode. Herein, we develop novel hierarchical ultrathin porous carbon shell anchored with RuO${}_2$ nanoparticles as efficient cathode hosts for lithium‐sulfur batteries. The carbon shell can allow efficient impregnation of sulfur and provide effective spatial confinement to reduce polysulfide diffusion. In addition, the volume expansion of sulfur upon lithiation can be also remitted due to the sufficient space inside the carbon shell. The anchored RuO${}_2$ nanoparticles in the host material can synergistically enhance the immobilization of polysulfide and accelerate their redox reaction. Accordingly, this hierarchical structure based‐cathode containing 70.6 wt% sulfur content delivers enhanced electrochemical performances including high specific capacity, excellent rate performance and superior cycling stability. (© 2019 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)