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Increased Capacity of LiNi 1/3 Co 1/3 Mn 1/3 O 2 –Li[Li 1/3 Mn 2/3 ]O 2 Cathodes by MnO x ‐surface Modification for Lithium‐Ion Batteries
Author(s) -
Wang Jun,
He Xin,
Kloepsch Richard,
Wang Sihui,
Hoffmann Bjoern,
Jeong Sangsik,
Yang Yong,
Li Jie
Publication year - 2014
Publication title -
energy technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.91
H-Index - 44
eISSN - 2194-4296
pISSN - 2194-4288
DOI - 10.1002/ente.201300127
Subject(s) - electrolyte , materials science , annealing (glass) , dissolution , analytical chemistry (journal) , cathode , metal , homogeneous , electrochemistry , electrode , chemistry , metallurgy , physics , thermodynamics , chromatography
Abstract MnO x ‐surface‐modified Li 1.2 Ni 0.4/3 Co 0.4/3 Mn 1.6/3 O 2 cathode materials have been prepared by solid‐state reaction with varying post‐annealing temperatures. The MnO x coating layers are homogeneous and crystalline with a thickness of 10 nm. Below a current rate of 0.1 C and in the voltage range of 2.0–4.8 V, the MnO x ‐modified material, which has been post‐annealed at 300 °C, shows high discharge capacities of 308, 320, and 363 mAh g −1 at 20, 40, and 60 °C, respectively. Meanwhile, this sample shows good rate capability that can deliver discharge capacities of 278 and 178 mAh g −1 , respectively, at 1 C and 10 C , both tested at 20 °C. However, the modified sample displays more serious capacity degradation compared to the pristine sample. The significantly higher extent of the transition metal dissolution from the modified sample is proved by compositional analysis. Cycling performance could be improved by replacing the conventional electrolyte with an ionic‐liquid‐based electrolyte.