Bio-inspired fabrication of carbon nanotiles for high performance cathode of Li–S batteries†
Learning from biological materials with complex, optimized and hierarchical morphologies and microstructures has become one of the hottest subjects in material design. Herein, we report a bio-inspired fabrication of fish scale-like carbon nanotiles, which were synthesized by a facile carbonization and grind procedure using kapok fibers (KFs) as green carbon source. Kapok fiber derived carbon nanotiles (KFCNTs) were used as the host of sulfur to construct KFCNTs/S cathodes for Li–S batteries. KFCNTs with scale-like microstructure are important for retarding the shuttling of soluble polysulfides, rendering S particles electrically conducting, and accommodating volume variation of S during the Li+ insertion/extraction. Owing to their unique microstructure, the resulting KFCNTs/S (93.2 wt%) electrodes exhibit a high and stable volumetric capacity of 504 mA h cm−3 (calculated from the whole electrode, the corresponding gravimetric capacity is 524 mA h g−1) with a superior capacity retention up to 95.4% after 90 cycles at 0.4 A g−1, representing a promising cathode material for rechargeable Li–S batteries. KFCNTs may also find potential applications in catalysis, electronics, sensors and separation technology. The bionic strategy outlined here can be generalized to other advanced electrode materials.