Three-dimensional porous carbon composites containing high sulfur nanoparticle content for high-performance lithium-sulfur batteries.

Guoxing Li,Jinhua Sun,Yong Huang,Shidong Jiang,Wenpeng Hou,Jianxin Geng

doi:10.1038/ncomms10601

Guoxing Li, Jinhua Sun + Show 4 more

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https://doi.org/10.1038/ncomms10601

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Abstract

Sulfur is a promising cathode material for lithium–sulfur batteries because of its high theoretical capacity (1,675 mA h g−1); however, its low electrical conductivity and the instability of sulfur-based electrodes limit its practical application. Here we report a facile in situ method for preparing three-dimensional porous graphitic carbon composites containing sulfur nanoparticles (3D S@PGC). With this strategy, the sulfur content of the composites can be tuned to a high level (up to 90 wt%). Because of the high sulfur content, the nanoscale distribution of the sulfur particles, and the covalent bonding between the sulfur and the PGC, the developed 3D S@PGC cathodes exhibit excellent performance, with a high sulfur utilization, high specific capacity (1,382, 1,242 and 1,115 mA h g−1 at 0.5, 1 and 2 C, respectively), long cycling life (small capacity decay of 0.039% per cycle over 1,000 cycles at 2 C) and excellent rate capability at a high charge/discharge current.

Highlights

Sulfur is a promising cathode material for lithium–sulfur batteries because of its high theoretical capacity (1,675 mA h g À 1); its low electrical conductivity and the instability of sulfur-based electrodes limit its practical application
The practical application of Li–S batteries is still handicapped by the following problems: (1) the low electrical conductivities of sulfur (5 Â 10 À 30 S cm À 1 at 25 °C), intermediate polysulphides and Li2S; (2) the dissolution of lithium polysulphides, which results in a shuttling effect and in the deposition of insoluble lithium sulfide on the anode in each of the charge/discharge cycles and eventually the complete loss of capacity of the sulfur cathode; and (3) severe volume changes in the active electrode materials during the lithiation/delithiation processes[1,4,5,6,7], resulting in the pulverization of the electrode materials
The self-stacking of water-soluble NaCl and Na2S crystals was utilized to form a hard template for the 3D porous graphitic carbon (PGC) network

Summary

Introduction

Sulfur is a promising cathode material for lithium–sulfur batteries because of its high theoretical capacity (1,675 mA h g À 1); its low electrical conductivity and the instability of sulfur-based electrodes limit its practical application. Because of the C–S bonds, unique interconnected hierarchical porous structures, high sulfur content and nanoscale sulfur particles, our 3D S@PGC (90% S) composite exhibits significantly improved electrochemical performance as a cathode material for Li–S batteries This material has a high specific capacity (1,382, 1,242 and 1,115 mA h g À 1 at 0.5, 1 and 2 C, respectively), long cycling life (small capacity decay of 0.039% per cycle over 1,000 cycles at 2 C), and excellent rate capability at a high charge/discharge current

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Conclusion