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Indexed by:期刊论文

Date of Publication:2018-12-21

Journal:JOURNAL OF MATERIALS CHEMISTRY A

Volume:6

Issue:47

Page Number:24194-24200

ISSN No.:2050-7488

Abstract:For lithium-sulfur (Li-S) batteries, it is critical to design advanced host materials with high conductivity and strong binding interactions with sulfur species to trap and convert the polysulfides efficiently. Here, we report a novel BN/CNTs hybrid with paragenesis structure, high surface area and O-doping via a one-step co-pyrolysis method. Such paragenesis structure can remarkably lower the contact resistance between non-conducting BN and conductive CNTs, and the O dopant in BN can narrow the bandgap of BN, both imparting the BN/CNTs hybrid a high conductivity of 1884 S m(-1). The BN/CNTs hybrid hosted sulfur shows monoclinic phase instead of the generally reported orthorhombic phase, implying a strong interaction between sulfur and the BN/CNTs hybrid. Moreover, the high surface and the O doping enable BN/CNTs hybrid to adsorb polysulfides with a superior capacity due to the polarization of electrons away from the sulfur atoms towards BN/CNTs. Thus, the BN/CNTs-sulfur cathode can deliver high specific capacity (1374 and 1068 mA h g(-1) at 0.2C and 1C, respectively), superior cycling stability (a constant coulombic efficiency of approximate to 99% and a decay rate of 0.045% per cycle along with 500 cycles at 1C) and excellent rate capability (840 mA h g(-1) at 4C). Moreover, it exhibits good high-sulfur-loading areal capacity (up to 4.5 mA h cm(-2)) with stable cell performance.