Zou Kunyang, Jing Weitao, Dai Xin, Chen Xinxing, Shi Ming, Yao Zhiyin, Zhu Ting, Sun Junjie, Chen Yuanzhen, Liu Yan, Liu Yongning
State Key Laboratory for Mechanical Behavior of Materials, School of Material Science and Engineering, Xi'an Jiaotong University, Xi'an, 710049, P. R. China.
Shaanxi Coal Chemical Industry Technology Research Institute Co., Ltd, Xi'an, 710100, P. R. China.
Small. 2022 Apr;18(17):e2107380. doi: 10.1002/smll.202107380. Epub 2022 Mar 25.
High energy density and long cycle life of lithium-sulfur (Li-S) batteries suffer from the shuttle/expansion effect. Sufficient sulfur storage space, local fixation of polysulfides, and outstanding electrical conductivity are crucial for a robust cathode host. Herein, a modified template method is proposed to synthesize a highly regular and uniform nitrogen/oxygen dual-doped honeycomb-like carbon as sulfur host (N/O-HC-S). The unique structure not only offers physical entrapment for polysulfides (LiPSs) but also provides chemical adsorption and catalytic conversion sites of polysulfides. In addition, this structure offers enough space for loading sulfur, and a regular space of nanometer size can effectively prevent sulfur particles from accumulating. As expected, the as-prepared N/O-HC900-S with high areal sulfur loading (7.4 mg cm ) shows a high areal specific capacity of 7.35 mAh cm at 0.2 C. Theoretical calculations also reveal that the strong chemical immobilization and catalytic conversion of LiPSs attributed to the spin density and charge distribution of carbon atoms will be influenced by the neighbor nitrogen/oxygen dopants. This structure that provides cooperative chemical adsorption, high lithium ions flux, and catalytic conversion for LiPSs can offer a new strategy for constructing a polysulfide confinement structure to achieve robust Li-S batteries.
锂硫（Li-S）电池的高能量密度和长循环寿命受到穿梭/膨胀效应的影响。足够的硫储存空间、多硫化物的局部固定以及出色的导电性对于坚固的阴极主体至关重要。在此，提出了一种改进的模板法来合成高度规则且均匀的氮/氧双掺杂蜂窝状碳作为硫主体（N/O-HC-S）。独特的结构不仅为多硫化物（LiPSs）提供物理截留，还提供多硫化物的化学吸附和催化转化位点。此外，这种结构为负载硫提供了足够的空间，纳米尺寸的规则空间可以有效防止硫颗粒聚集。正如预期的那样，所制备的具有高面硫负载量（7.4 mg cm ）的N/O-HC900-S在0.2 C下显示出7.35 mAh cm 的高面比容量。理论计算还表明，归因于碳原子自旋密度和电荷分布的LiPSs的强化学固定和催化转化将受到相邻氮/氧掺杂剂的影响。这种为LiPSs提供协同化学吸附、高锂离子通量和催化转化的结构可为构建多硫化物限制结构以实现坚固的Li-S电池提供新策略。
