title: Surface Surgery of the Nickel-Rich Cathode Material LiNi0.815Co0.15Al0.035O2: Toward a Complete and Ordered Surface Layered Structure and Better Electrochemical Properties.
abstract: A complete and ordered layered structure on the surface of LiNi0.815Co0.15Al0.035O2(NCA) has been achieved via a facile surface-oxidation method with Na2S2O8. The field-emission transmission electron microscopy images clearly show that preoxidation of the hydroxide precursor can eliminate the crystal defects and convert Ni(OH)2into layered β-NiOOH, which leads to a highly ordered crystalline NCA, with its (006) planes perpendicular to the surface in the sintering process. X-ray photoelectron spectroscopy and Raman shift results demonstrate that the contents of Ni2+and Co2+ions are reduced with preoxidization on the surface of the hydroxide precursor. The level of Li+/Ni2+disordering in the modified NCA determined by the peak intensity ratio I(003)/I(104)in X-ray diffraction patterns decreases. Thanks to the complete and ordered layered structure on the surface of secondary particles, lithium ions can easily intercalate/extract in the discharging-charging process, leading to greatly improved electrochemical properties.
authors.affiliation: CAS Key Laboratory of Materials for Energy Conversions, Department of Materials Science and Engineering, and Collaborative Innovation Center of Suzhou Nano Science and Technology, University of Science and Technology of China , Anhui, Hefei 230026, China.
authors.forename: Zhongfeng
authors.initials: Z
authors.lastname: Tang
authors.affiliation: CAS Key Laboratory of Materials for Energy Conversions, Department of Materials Science and Engineering, and Collaborative Innovation Center of Suzhou Nano Science and Technology, University of Science and Technology of China , Anhui, Hefei 230026, China.|School of Chemistry and Chemical Engineering, Anhui University , Anhui, Hefei 230601, China.
authors.forename: Junjie
authors.initials: J
authors.lastname: Bao
authors.affiliation: CAS Key Laboratory of Materials for Energy Conversions, Department of Materials Science and Engineering, and Collaborative Innovation Center of Suzhou Nano Science and Technology, University of Science and Technology of China , Anhui, Hefei 230026, China.
authors.forename: Qingxia
authors.initials: Q
authors.lastname: Du
authors.affiliation: CAS Key Laboratory of Materials for Energy Conversions, Department of Materials Science and Engineering, and Collaborative Innovation Center of Suzhou Nano Science and Technology, University of Science and Technology of China , Anhui, Hefei 230026, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Shao
authors.affiliation: School of Chemistry and Chemical Engineering, Anhui University , Anhui, Hefei 230601, China.
authors.forename: Minghao
authors.initials: M
authors.lastname: Gao
authors.affiliation: CAS Key Laboratory of Materials for Energy Conversions, Department of Materials Science and Engineering, and Collaborative Innovation Center of Suzhou Nano Science and Technology, University of Science and Technology of China , Anhui, Hefei 230026, China.
authors.forename: Bangkun
authors.initials: B
authors.lastname: Zou
authors.affiliation: CAS Key Laboratory of Materials for Energy Conversions, Department of Materials Science and Engineering, and Collaborative Innovation Center of Suzhou Nano Science and Technology, University of Science and Technology of China , Anhui, Hefei 230026, China.
authors.forename: Chunhua
authors.identifier: http://orcid.org/0000-0001-9589-6329
authors.initials: C
authors.lastname: Chen
keywords: cation disorder; crystal defect; lithium-ion battery; lithium−nickel−cobalt aluminum oxide; sodium peroxodisulfate; surface oxidation