Fabricating a Carbon Microtube Interlayer by a Sustainable Green Process as a Polysulfide-Trapping Shield for Lithium-Sulfur Batteries

The shuttle effect of polysulfides in lithium-sulfur batteries (LSBs) leads to unsatisfactory electrochemical performance. Herein, hierarchical hollow carbon microtubes (CMTs) are simply prepared by carbonization of willow catkins and coated on a commercialized separator for high-performance LSBs. The CMTs-coated separator can inhibit the diffusion of polysulfides through physical and chemical adsorption, which alleviates the shuttle effect effectively. In addition, the CMTs interlayer acts as an upper current collector to provide continuous highways for electron and ion transport to enhance the utilization of active materials. As a result, the cells with a CMTs-coated separator exhibit a high discharge specific capacity of 800 mAh g(-1) after 100 cycles at 0.2 A g(-1), which is higher than the capacity (554 mAh g(-1)) of the cell with the pristine separator. This work not only provides a green process to produce sustainable and low-cost hollow CMTs but also designs high-performance LSBs based on the obtained CMTs.