A polypyrrole/black-TiO2/S double-shelled composite fixing polysulfides for lithium-sulfur batteries
A polypyrrole/black-TiO2/S double-shelled composite fixing polysulfides for lithium-sulfur batteries
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DOI：
10.1016/j.electacta.2020.136529
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发表时间：
2020-09
影响因子：
6.6
通讯作者：
Tong Wu;Guiru Sun;W. Lu;Liping Zhao;A. Mauger;C. Julien;Liqun Sun;Haiming Xie;Jinghai Liu
中科院分区：
文献类型：
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作者：
Tong Wu;Guiru Sun;W. Lu;Liping Zhao;A. Mauger;C. Julien;Liqun Sun;Haiming Xie;Jinghai Liu
抑制多硫化锂（LiPS）的穿梭和提高正极的电导率是提高锂硫电池性能的理想途径。在目前的工作中，我们报告了一个阴极同时作为一个高效的LiPSs固定剂和硫主机。它是由硫嵌入一个中空的球体，其外壳是由中空的黑色TiO 2（b-TiO 2）球形纳米粒子。然后用聚吡咯（PPy）层涂覆复合物的颗粒以形成活性阴极元件（b-TiO 2/S@PPy）。b-TiO 2层的特殊拓扑结构提供了足够的空间来缓解LiPS的体积膨胀。PPy包覆层不仅可以提高LiPS阴极的电导率，而且可以通过化学吸附抑制LiPS的穿梭。当硫含量为59.6wt%（对应于1.5-1.8 mg cm-2的硫负载量）时，具有b-TiO 2/S@PPy阴极的锂硫电池表现出高的初始放电容量（0.1C下1374 mAh g-1）、上级的循环稳定性（0.1C下200次循环后910 mAh g-1）和良好的倍率性能（2C下725 mAh g-1）。
The inhibition of the shuttle of lithium polysulfides (LiPSs) and enhancement of the electrical conductivity of the cathodes are desirable to improve the performance of lithium-sulfur batteries. In the present work, we report a cathode acting simultaneously as a highly efficient LiPSs immobilizer and sulfur host. It is composed of sulfur embedded inside a hollow sphere, the shell of which is made of hollow black TiO2(b-TiO2) spherical nanoparticles. The particles of the composite are then coated with a polypyrrole (PPy) layer to form the active cathode element (b-TiO2/S@PPy). The particular topology of the b-TiO2layer provides enough space to alleviate the volume expansion of LiPSs. Equally, the PPy coating layer can not only improve the conductivity of the cathodes, but also restrain the shuttle of LiPSs by chemical adsorption. With the sulfur content of 59.6 wt% corresponding to a sulfur loading of 1.5–1.8 mg cm−2, the lithium-sulfur batteries with the b-TiO2/S@PPy cathode exhibits a high initial discharge capacity (1374 mAh g−1at 0.1C), a superior cycling stability (910 mAh g−1after 200 cycles at 0.1C), and a good rate performance (725 mAh g−1at 2C).