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A Novel Surface Treatment Method and New Insight into Discharge Voltage Deterioration for High‐Performance 0.4Li 2 MnO 3– 0.6LiNi 1/3 Co 1/3 Mn 1/3 O 2 Cathode Materials
Author(s) -
Oh Pilgun,
Ko Minseong,
Myeong Seungjun,
Kim Youngsik,
Cho Jaephil
Publication year - 2014
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201400631
Subject(s) - materials science , cathode , faraday efficiency , electrochemistry , oxide , coating , chemical engineering , graphene , surface modification , surface layer , layer (electronics) , nanotechnology , electrode , metallurgy , chemistry , engineering
The Li‐rich cathode materials have been considered as one of the most promising cathodes for high energy Li‐ion batteries. However, realization of these materials for use in Li‐ion batteries is currently limited by their intrinsic problems. To overcome this barrier, a new surface treatment concept is proposed in which a hybrid surface layer composed of a reduced graphene oxide (rGO) coating and a chemically activated layer is created. A few layers of GO are first coated on the surface of the Li‐rich cathode material, followed by a hydrazine treatment to produce the reducing agent of GO and the chemical activator of the Li 2 MnO 3 phase. Compared to previous studies, this surface treatment provides substantially improved electrochemical performance in terms of initial Coulombic effiency and retention of discharge voltage. As a result, the surface‐treated 0.4Li 2 MnO 3– 0.6LiNi 1/3 Co 1/3 Mn 1/3 O 2 exhibits a high capacity efficiency of 99.5% during the first cycle a the discharge capacity of 250 mAh g −1 (2.0–4.6 V under 0.1C), 94.6% discharge voltage retention during 100 cycles (1C) and the superior capacity retention of 60% at 12C at 24 °C.