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Multifunctional Co 3 S 4 /Graphene Composites for Lithium Ion Batteries and Oxygen Reduction Reaction
Author(s) -
Mahmood Nasir,
Zhang Chenzhen,
Jiang Jie,
Liu Fei,
Hou Yanglong
Publication year - 2013
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201204549
Subject(s) - graphene , materials science , faraday efficiency , electrochemistry , dielectric spectroscopy , lithium (medication) , composite material , conductivity , chemical engineering , electrode , nanotechnology , chemistry , medicine , endocrinology , engineering
Cobalt sulfide is a good candidate for both lithium ion batteries (LIBs) and cathodic oxygen reduction reaction (ORR), but low conductivity, poor cyclability, capacity fading, and structural changes hinder its applications. The incorporation of graphene into Co 3 S 4 makes it a promising electrode by providing better electrochemical coupling, enhanced conductivity, fast mobility of ions and electrons, and a stabilized structure due to its elastic nature. With the objective of achieving high‐performance composites, herein we report a facile hydrothermal process for growing Co 3 S 4 nanotubes (NTs) on graphene (G) sheets. Electrochemical impedance spectroscopy (EIS) verified that graphene dramatically increases the conductivity of the composites to almost twice that of pristine Co 3 S 4 . Electrochemical measurements indicated that the as‐synthesized Co 3 S 4 /G composites exhibit good cyclic stability and a high discharge capacity of 720 mA h g −1 up to 100 cycles with 99.9 % coulombic efficiency. Furthermore, the composites react with dissolved oxygen in the ORR by four‐ and two‐electron mechanisms in both acidic and basic media with an onset potential close to that of commercial Pt/C. The stability of the composites is much higher than that of Pt/C, and exhibit high methanol tolerance. Thus, these properties endorse Co 3 S 4 /G composites as auspicious candidates for both LIBs and ORR.