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Reduction of Charge and Discharge Polarization by Cobalt Nanoparticles‐Embedded Carbon Nanofibers for Li–O 2 Batteries
Author(s) -
Kim YunJung,
Lee Hongkyung,
Lee Dong Jin,
Park JungKi,
Kim HeeTak
Publication year - 2015
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201500520
Subject(s) - cobalt , nanoparticle , materials science , carbon nanofiber , polarization (electrochemistry) , nanofiber , carbon fibers , chemical engineering , nanotechnology , inorganic chemistry , chemistry , carbon nanotube , composite material , composite number , engineering
The problem of high charge polarization is one of the most significant challenges in current nonaqueous Li–O 2 batteries. The development of an electrode for the oxygen evolution reaction (OER) at reduced overpotential is thus essential. Here, we suggest a binder‐free electrode based on Co nanoparticles embedded in carbon nanofibers (Co–CNFs), which simultaneously reduces the charge and discharge polarization and extends cycling stability. Co–CNF gives rise to a lower discharge polarization because of an enhanced oxygen reduction reaction activity compared to Co‐free CNF. Although the embedment of Co does not enhance the OER activity, it significantly reduces charge overvoltage by forming easily decomposable amorphous Li 2 O 2 . A mechanism for the formation of amorphous Li 2 O 2 is suggested in terms of charge localization induced by the Co NPs. The findings suggest a new electrode design strategy of combining inexpensive metals and carbon materials for modulating the phase of the discharge product.