Details

Autor(en) / Beteiligte

• Du, Xinyu
• Zhang, Xiaolong
• Guo, Junling
• Zhao, Shupeng
• Zhang, Fengxiang

Titel

Hierarchical sulfur confinement by graphene oxide wrapped, walnut-like carbon spheres for cathode of Li-S battery

Ist Teil von

• Journal of alloys and compounds, 2017-08, Vol.714, p.311-317

Ort / Verlag

Lausanne: Elsevier B.V

Erscheinungsjahr

2017

Link zum Volltext

Quelle

Elsevier ScienceDirect Journals Complete

Beschreibungen/Notizen

• Inadequate cycle stability is a major issue hindering practical application of lithium sulfur (Li-S) batteries. We herein report a graphene oxide wrapped, multi-cavity, walnut-like carbon sphere (GO-MCWCS) cathode which may help to alleviate the above issue. The multi-cavity, walnut-like carbon spheres were obtained through a templated sol-gel process. Sulfur and polysulfides (the discharge intermediate at the cathode) are effectively immobilized in the GO-MCWCS cathode through a hierarchical mode of confinement, i.e. multiple levels of physical confinement by the abundant cavities of the walnut-like structure and the graphene oxide wrapping layer. The functional groups on GO (such as epoxy and hydroxyl groups) also help to retain polysulfides in the cathode via chemical binding. Attributed to the rational design of the GO-MCWCS cathode, our Li-S battery displayed an excellent cycle performance (85% capacity retention and nearly 100% coulombic efficiency after 200 cycles at 0.5C) and a good rate capability (905 mAh g−1 and 680 mAh g−1 at 1C and 2C, respectively). It is believed that the novel GO-MCWCS composite structure is a promising cathode design for advanced Li-S batteries. Due to hierarchical sulfur and polysulfide confinement effects, walnut-like carbon sphere wrapped by graphene oxide as Li/S battery cathode displays excellent cycle performance (85% capacity retention and nearly 100% coulombic efficiency after 200 cycles). [Display omitted] •Graphene oxide wrapped, multi-cavity, walnut-like carbon spheres synthesized.•Hierarchical confinement of sulfur and polysulfides in the above structure.•Improved rate capability due to GO enabled, better sulfur-carbon contact.•Discharge capacity remaining above 1027 mAh g−1 after 200 cycles at 0.5 C.