Free-Standing Nitrogen-doped Graphene Paper as Electrodes for High-Performance Lithium/Dissolved Polysulfide Batteries

• Published in: ChemSusChem Vol. 7; no. 9; pp. 2545 - 2553
• Main Authors: Han, Kai, Shen, Jingmei, Hao, Shiqiang, Ye, Hongqi, Wolverton, Christopher, Kung, Mayfair C., Kung, Harold H.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.09.2014; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Subjects: binder-free; catholyte; Electric Power Supplies; Electrodes; free-standing; Graphite - chemistry; Li/polysulfide battery; Lithium - chemistry; Models, Molecular; Molecular Conformation; N-doped graphene; Nitrogen - chemistry; Spectrum analysis; Sulfides - chemistry; X-rays; catholyte; Li/polysulfide battery; free-standing; N-doped graphene; binder-free
• ISSN: 1864-5631; 1864-564X
• DOI: 10.1002/cssc.201402329

Free‐standing N‐doped graphene papers (NGP), generated by pyrolysis of polydiallyldimethylammonium chloride, were successfully used as binder‐free electrodes for the state‐of‐the‐art Li/polysulfide‐catholyte batteries. They exhibited high specific capacities of approximately1000 mA h g−1 (based on S) after 100 cycles and coulombic efficiencies great than 98 %, significantly better than undoped graphene paper (GP). These NGP were characterized with XRD, X‐ray photoelectron spectroscopy, thermogravimetric analysis, AFM, electron microscopy, and Raman and impedance spectroscopy before and after cycling. Spectroscopic evidence suggested stronger binding of sulfide to NGP relative to GP, and modelling results from DFT calculation, substantiated with experimental data, indicated that pyrrolic and pyridinic N atoms interacted more strongly with Li polysulfides than quaternary N atoms. Thus, more favorable partition of polysulfides between the electrode and the electrolyte and the corresponding effect on the morphology of the passivation layer were the causes of the beneficial effect of N doping. Get out of a bind: A binder‐free N‐doped graphene has been synthesized to use as electrodes for Li/dissolved polysulfides battery. The N‐doped graphene was found to have a larger capacity to adsorb polysulfide, lower electrolyte resistance, and much slower growth of passivation film resistance. The cell exhibited superior electrochemical performance with high specific capacities and coulombic efficiencies.