Hierarchical Porous Carbon Materials Derived from Self-Template Bamboo Leaves for Lithium-Sulfur Batteries

Lithium-sulfur (Li-S) batteries are attractive and promising energy storage devices due to the large theoretical energy density (2600 Wh kg(-1))and natural abundance of sulfur. However, several intrinsic drawbacks hamper broader application, for example, the poor conductivity, serious shuttle effect, as well as large volume expansion. In this work, hierarchical porous carbon materials (HPCMs) are prepared from natural bamboo leaves by carbonization and HF etching. The biogenetic SiO2 nanoparticles (NPs) with abundant mesopores in the carbonized bamboo leaves are etched by HF producing hierarchical meso-/microporous carbon that can be exploited to load sulfur on the nanoscale. The HPCMs/S composite loaded with 70.26 wt. % sulfur shows a high initial discharge capacity of 1487 mAhg(-1) at a rate of 0.05C (1C =1675 mAg(-1)) and the capacity of 707 mAh g(-1) is maintained at 1C for over 200 cycles with a capacity decay of only 0.014% per cycle. When the current density is increased from 0.2 to 4C, 623% of the capacity is retained, suggesting good rate capability and promising application to advanced Li-S batteries. (C) 2017 Elsevier Ltd. All rights reserved.