期刊
NANO LETTERS
卷 17, 期 1, 页码 437-444出版社
AMER CHEMICAL SOC
DOI: 10.1021/acs.nanolett.6b04433
关键词
Lithium-sulfur batteries; polysulfide trapping; hierarchical micromesopores; carbon nanotube/nanopolyhedra superstructures
类别
资金
- National Materials Genome Project [2016YFB0700600]
- National 973 Basic Research Program [2015CB659300]
- National Natural Science Foundation of China [21403105, 21573108]
- China Postdoctoral Science Foundation [2015M581768, 2015M580413]
- Natural Science Foundation for Young Scholars of Jiangsu Province [BK20150583, BK20160647]
- Fundamental Research Funds for the Central Universities
- Priority Academic Program Development (PAPD) of Jiangsu Higher Education Institutions
Despite high theoretical energy density, the practical deployment of lithium-sulfur (Li-S) batteries is still not implemented because of the severe capacity decay caused by polysulfide shuttling and the poor rate capability induced by low electrical conductivity of sulfur. Herein, we report a novel sulfur host material based on sea urchin-like cobalt nanoparticle embedded and nitrogen-doped carbon nanotube/nanopolyhedra (Co-NCNT/NP) superstructures for Li-S batteries. The hierarchical micromesopores in Co-NCNT/NP can allow efficient impregnation of sulfur and block diffusion of soluble polysulfides by physical confinement, and the incorporation of embedded Co nanoparticles and nitrogen doping (similar to 4.6 at %) can synergistically improve the adsorption of polysulfides, as evidenced, by beaker cell tests. Moreover, the conductive networks of Co-NCNT/NP interconnected by nitrogen-doped carbon nanotubes (NCNTs) can facilitate electron transport and electrolyte infiltration. Therefore, the specific capacity, rate capability, and cycle stability of Li-S batteries are significantly enhanced. As a result, the Co-NCNT/NP based cathode (loaded with 80 wt % sulfur) delivers a high discharge capacity of 1240 mAh g(-1) after 100 cycles at 0.1 C (based on the weight of sulfur), high rate capacity (755 mAh g(-1) at 2.0 C), and ultralong cycling life (a very low capacity decay of 0.026% per cycle over 1500 cycles at 1.0 C). Remarkably, the composite cathode with high areal sulfur loading of 3.2 mg cm(-2) shows high rate capacities and stable cycling performance over 200 cycles.
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