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Li–Ti Cation Mixing Enhanced Structural and Performance Stability of Li‐Rich Layered Oxide
Author(s) -
Liu Shuai,
Liu Zepeng,
Shen Xi,
Wang Xuelong,
Liao ShengChieh,
Yu Richeng,
Wang Zhaoxiang,
Hu Zhiwei,
Chen ChienTe,
Yu Xiqian,
Yang Xiaoqing,
Chen Liquan
Publication year - 2019
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.201901530
Subject(s) - materials science , oxide , cathode , ion , scanning transmission electron microscopy , metal , lithium (medication) , transition metal , transmission electron microscopy , mixing (physics) , absorption spectroscopy , chemical physics , analytical chemistry (journal) , nanotechnology , chemistry , optics , physics , quantum mechanics , medicine , biochemistry , organic chemistry , chromatography , endocrinology , catalysis , metallurgy
Li‐rich layered metal oxides are one type of the most promising cathode materials in lithium‐ion batteries but suffer from severe voltage decay during cycling because of the continuous transition metal (TM) migration into the Li layers. A Li‐rich layered metal oxide Li 1.2 Ti 0.26 Ni 0.18 Co 0.18 Mn 0.18 O 2 (LTR) is hereby designed, in which some of the Ti 4+ cations are intrinsically present in the Li layers. The native Li–Ti cation mixing structure enhances the tolerance for structural distortion and inhibits the migration of the TM ions in the TMO 2 slabs during (de)lithiation. Consequently, LTR exhibits a remarkable cycling stability of 97% capacity retention after 182 cycles, and the average discharge potential drops only 90 mV in 100 cycles. In‐depth studies by electron energy loss spectroscopy and aberration‐corrected scanning transmission electron microscopy demonstrate the Li–Ti mixing structure. The charge compensation mechanism is uncovered with X‐ray absorption spectroscopy and explained with the density function theory calculations. These results show the superiority of introducing transition metal ions into the Li layers in reinforcing the structural stability of the Li‐rich layered metal oxides. These findings shed light on a possible path to the development of Li‐rich materials with better potential retention and a longer lifespan.