title: Multi-Functional Surface Engineering for Li-Excess Layered Cathode Material Targeting Excellent Electrochemical and Thermal Safety Properties.
abstract: The Li(Li(0.18)Ni(0.15)Co(0.15)Mn(0.52))O2 cathode material is modified by a Li4M5O12-like heterostructure and a BiOF surface layer. The interfacial heterostructure triggers the layered-to-Li4M5O12 transformation of the material which is different from the layered-to-LiMn2O4 transformation of the pristine Li(Li(0.18)Ni(0.15)Co(0.15)Mn(0.52))O2. This Li4M5O12-like transformation helps the material to keep high working voltage, long cycle life and excellent rate capability. Mass spectrometry, in situ X-ray diffraction and transmission electron microscope show that the Li4M5O12-like phase prohibits oxygen release from the material bulk at elevated temperatures. In addition, the BiOF coating layer protects the material from harmful side reactions with the electrolyte. These advantages significantly improve the electrochemical performance of Li(Li(0.18)Ni(0.15)Co(0.15)Mn(0.52))O2. The material shows a discharge capacity of 292 mAh g(-1) at 0.2 C with capacity retention of 92% after 100 cycles. Moreover, a high discharge capacity of 78 mAh g(-1) could be obtained at 25 C. The exothermic temperature of the fully charged electrode is elevated from 203 to 261 °C with 50% reduction of the total thermal release, highlighting excellent thermal safety of the material.
authors.affiliation: Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University , Changchun 130012, People's Republic of China.
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Bian
authors.affiliation: Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University , Changchun 130012, People's Republic of China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Fu
authors.affiliation: Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University , Changchun 130012, People's Republic of China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Pang
authors.affiliation: Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University , Changchun 130012, People's Republic of China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University , Changchun 130012, People's Republic of China.
authors.forename: Yingjin
authors.initials: Y
authors.lastname: Wei
authors.affiliation: State Key Laboratory of Superhard Materials, Jilin University , Changchun 130012, People's Republic of China.
authors.forename: Bo
authors.initials: B
authors.lastname: Zou
authors.affiliation: Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University , Changchun 130012, People's Republic of China.
authors.forename: Fei
authors.initials: F
authors.lastname: Du
authors.affiliation: Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University , Changchun 130012, People's Republic of China.|State Key Laboratory of Superhard Materials, Jilin University , Changchun 130012, People's Republic of China.
authors.forename: Gang
authors.initials: G
authors.lastname: Chen
keywords: Li-excess layered oxide; electrochemical properties; lithium ion battery; surface modification; thermal safety