MnO modified carbon nanotubes as a sulfur host with enhanced performance in Li/S batteries

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 4; no. 33; pp. 12858 - 12864
• Main Authors: An, Taihua, Deng, Dingrong, Lei, Ming, Wu, Qi-Hui, Tian, Zhaowu, Zheng, Mingsen, Dong, Quanfeng
• Format: Journal Article
• Language: English
• Published: 01.01.2016
• Subjects: adsorption; Carbon; Carbon nanotubes; Cathodes; Electric batteries; electrical conductivity; electrochemistry; energy density; High current; Lithium; lithium batteries; manganese oxides; nanoparticles; Polysulfides; Sulfur; surface area
• ISSN: 2050-7488; 2050-7496; 2050-7496
• DOI: 10.1039/c6ta04445j

Lithium/sulfur (Li/S) batteries have become promising future power sources owing to the high energy density. Carbon materials are the most used sulfur hosts, but their ability to adsorb polysulfide intermediates has been unreliable, thus recently many researchers have turned their interest to metal oxide materials. Here, we manufactured a composite of carbon nanotubes modified with manganese oxide nanoparticles (CNTs/MnO) as a sulfur host material. In Li/S cells, the CNTs/MnOS cathode showed a rather better cycling stability over 100 cycles than a CNTsS cathode with the same carbon/sulfur weight ratio of about 1:8. In addition, the CNTs/MnOS cathode presented an initial discharge capacity of 716 mA h g 1 at a high current density of 5.0C, in contrast to the result of only 415 mA h g 1 with the CNTsS cathode. Physical and electrochemical characterization proved that the MnO modification does not vary the surface area of the CNTs but lowers their electrical conductivity. By carefully comparing the differences in the 1 st discharge capacities of the two cathodes, the MnO modification could obviously improve the initial utilization of S especially at high current densities. The improved electrochemical characteristics of the CNTs/MnOS electrode can be attributed to its properties of a stronger adsorption capability for polysulfides. MnO modified CNTs are applied as an efficient sulfur host to improve the performance of Li/S batteries due to the strong polysulfide adsorbability.