Stable Cycling of a Scalable Graphene-Encapsulated Nanocomposite for Lithium-Sulfur Batteries
Stable Cycling of a Scalable Graphene-Encapsulated Nanocomposite for Lithium-Sulfur Batteries
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DOI：
10.1021/am500632b
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发表时间：
2014-07-23
影响因子：
9.5
通讯作者：
Nazar, Linda F.
中科院分区：
文献类型：
--
作者：
He, Guang;Hart, Connor J.;Nazar, Linda F.
我们报道了一种低成本的碳/硫纳米复合材料的合成，以Ketjen黑（KBC）为碳框架，通过一个简单的工艺，将功能化的KBC/S纳米颗粒表面与氧化石墨烯（GO）结合，在原位还原。略微过量的氧化石墨烯被用来在KBC/S周围形成第二层石墨烯。这种g- kbc /S硫阴极在200次循环中表现出优异的可循环性，平均稳定衰减率仅为0.026%或1.1 mAh g（-1）。这种优异的性能主要归功于包裹的内部多孔结构。介孔KBC阵列的大孔体积、小孔径和均匀的纳米颗粒尺寸为制备均匀的C/S复合材料提供了理想的框架，而石墨烯/氧化石墨烯片则是抑制多硫化物扩散的外部化学和物理屏障。
We report the synthesis of a low-cost carbon/sulfur nanocomposite using Ketjen black (KBC) as the carbon framework, encapsulated by thin graphene sheets using a simple process that relies on binding a functionalized KBC/S nanoparticle surface with graphene oxide (GO), which is reduced in situ. A slight excess of GO is employed to create a second layer of graphene wrapping around the KBC/S. This g-KBC/S sulfur cathode exhibits excellent cyclability over 200 cycles where the average stabilized fade rate is only 0.026% or 1.1 mAh g(-1) per cycle. This excellent performance is primarily attributed to the wrapped, internally porous architecture. The large pore volume, small pore diameter, and uniform nanoparticle size of the mesoporous KBC array provides an ideal frame for the fabrication of a homogeneous C/S composite, whereas the graphene/GO sheets serve as an external chemical and physical barrier that inhibits polysulfide diffusion.