title: Hierarchically porous carbon encapsulating sulfur as a superior cathode material for high performance lithium-sulfur batteries.
abstract: Lithium-sulfur (Li-S) batteries are deemed to be a promising energy storage device for next-generation high energy power system. However, insulation of S and dissolution of lithium polysulfides in the electrolyte lead to low utilization of sulfur and poor cycling performance, which seriously hamper the rapid development of Li-S batteries. Herein, we reported that encapsulating sulfur into hierarchically porous carbon (HPC) derived from the soluble starch with a template of needle-like nanosized Mg(OH)2. HPC has a relatively high specific surface area of 902.5 m(2) g(-1) and large total pore volume of 2.60 cm(3) g(-1), resulting that a weight percent of sulfur in S/HPC is up to 84 wt %. When evaluated as cathodes for Li-S batteries, the S/HPC composite has a high discharge capacity of 1249 mAh g(-1) in the first cycle and a Coulombic efficiency as high as 94% with stable cycling over prolonged 100 charge/discharge cycles at a high current density of 1675 mA g(-1). The superior electrochemical performance of S/HPC is closely related to its unique structure, exhibiting the graphitic structure with a high developed porosity framework of macropores in combination with mesopores and micropores. Such nanostructure could shorten the transport pathway for both ions and electrons during prolonged cycling.
authors.affiliation: College of Materials Science & Engineering, Nanjing University of Aeronautics and Astronautics , Nanjing, 210016, P. R. China.
authors.forename: Guiyin
authors.initials: G
authors.lastname: Xu
authors.forename: Bing
authors.initials: B
authors.lastname: Ding
authors.forename: Ping
authors.initials: P
authors.lastname: Nie
authors.forename: Laifa
authors.initials: L
authors.lastname: Shen
authors.forename: Hui
authors.initials: H
authors.lastname: Dou
authors.forename: Xiaogang
authors.initials: X
authors.lastname: Zhang