A study of the structure–activity relationship of the electrochemical performance and Li/Ni mixing of lithium-rich materials by neutron diffraction. Issue 39 (1st April 2015)

• Record Type: Journal Article
• Authors: Zhao, Enyue; Hu, Zhongbo; Xie, Lei; Chen, Xiping; Xiao, Xiaoling; Liu, Xiangfeng
• Is Part Of: RSC advances. Volume 5:Issue 39(2015)
• Page Start: 31238
• Page End: 31244
• Publication Date: 2015-04-01
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c5ra02380g
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : 4 mol% Mg-doped and 1 mol% Al-doped lithium-rich 0.3Li2 MnO3 ·0.7LiNi0.5 Mn0.5 O2 materials exhibit enhanced electrochemical performance due to reduced Li/Ni mixing. Abstract : 0.3Li2 MnO3 ·0.7LiNi0.5− x Mn0.5− x M2 x O2 (M = Mg or Al, x = 0–0.08) samples have been synthesized by a combination of co-precipitation (CP) and solid-state reaction. Electrochemical measurements show that not only can the charge–discharge capacity of lithium-rich materials be enhanced, but more importantly, the rate capacity can be greatly improved by doping with magnesium and aluminum. At a current density of 400 mA g −1, the 0.3Li2 MnO3 ·0.7LiNi0.46 Mn0.46 Mg0.08 O2 and 0.3Li2 MnO3 ·0.7LiNi0.49 Mn0.49 Al0.02 O2 electrodes deliver discharge capacities of 135 mA h g −1 and 127 mA h g −1, respectively, while the pristine electrode delivers a discharge capacity of only 10 mA h g −1 . Through studying the structure of lithium-rich materials, we find that the Li/Ni mixing of lithium-rich materials is reduced by doping with magnesium and aluminum, in turn, the performance of doped lithium-rich materials is improved greatly. Furthermore, compared with Al-doped lithium-rich materials, the Li/Ni mixing of Mg-doped materials is further reduced. So the performance improvement of Mg-doped lithium-rich materials is more obvious than that of Al-doped materials.