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An Ion‐Exchange Promoted Phase Transition in a Li‐Excess Layered Cathode Material for High‐Performance Lithium Ion Batteries
Author(s) -
Zhao Jianqing,
Huang Ruiming,
Gao Wenpei,
Zuo JianMin,
Zhang Xiao Feng,
Misture Scott T.,
Chen Yuan,
Lockard Jenny V.,
Zhang Boliang,
Guo Shengmin,
Khoshi Mohammad Reza,
Dooley Kerry,
He Huixin,
Wang Ying
Publication year - 2015
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.201401937
Subject(s) - materials science , spinel , electrochemistry , lithium (medication) , cathode , ion , oxide , phase (matter) , lithium oxide , chemical engineering , phase transition , transmission electron microscopy , analytical chemistry (journal) , electrode , lithium vanadium phosphate battery , nanotechnology , chemistry , metallurgy , thermodynamics , medicine , physics , organic chemistry , engineering , chromatography , endocrinology
A new approach to intentionally induce phase transition of Li‐excess layered cathode materials for high‐performance lithium ion batteries is reported. In high contrast to the limited layered‐to‐spinel phase transformation that occurred during in situ electrochemical cycles, a Li‐excess layered Li[Li 0.2 Mn 0.54 Ni 0.13 Co 0.13 ]O 2 is completely converted to a Li 4 Mn 5 O 12 ‐type spinel product via ex situ ion‐exchanges and a post‐annealing process. Such a layered‐to‐spinel phase conversion is examined using in situ X‐ray diffraction and in situ high‐resolution transmission electron microscopy. It is found that generation of sufficient lithium ion vacancies within the Li‐excess layered oxide plays a critical role for realizing a complete phase transition. The newly formed spinel material exhibits initial discharge capacities of 313.6, 267.2, 204.0, and 126.3 mAh g −1 when cycled at 0.1, 0.5, 1, and 5 C (1 C = 250 mA g −1 ), respectively, and can retain a specific capacity of 197.5 mAh g −1 at 1 C after 100 electrochemical cycles, demonstrating remarkably improved rate capability and cycling stability in comparison with the original Li‐excess layered cathode materials. This work sheds light on fundamental understanding of phase transitions within Li‐excess layered oxides. It also provides a novel route for tailoring electrochemical performance of Li‐excess layered cathode materials for high‐capacity lithium ion batteries.