title: High-Performance Heterostructured Cathodes for Lithium-Ion Batteries with a Ni-Rich Layered Oxide Core and a Li-Rich Layered Oxide Shell.
abstract: The Ni-rich layered oxides with a Ni content of >0.5 are drawing much attention recently to increase the energy density of lithium-ion batteries. However, the Ni-rich layered oxides suffer from aggressive reaction of the cathode surface with the organic electrolyte at the higher operating voltages, resulting in consequent impedance rise and capacity fade. To overcome this difficulty, we present here a heterostructure composed of a Ni-rich LiNi0.7Co0.15Mn0.15O2core and a Li-rich Li1.2-xNi0.2Mn0.6O2shell, incorporating the advantageous features of the structural stability of the core and chemical stability of the shell. With a unique chemical treatment for the activation of the Li2MnO3phase of the shell, a high capacity is realized with the Li-rich shell material. Aberration-corrected scanning transmission electron microscopy (STEM) provides direct evidence for the formation of surface Li-rich shell layer. As a result, the heterostructure exhibits a high capacity retention of 98% and a discharge-voltage retention of 97% during 100 cycles with a discharge capacity of 190 mA h g-1(at 2.0-4.5 V under C/3 rate, 1C = 200 mA g-1).
authors.affiliation: Materials Science and Engineering Program & Texas Materials Institute The University of Texas at Austin Austin TX 78712 USA.
authors.forename: Pilgun
authors.initials: P
authors.lastname: Oh
authors.affiliation: Materials Science and Engineering Program & Texas Materials Institute The University of Texas at Austin Austin TX 78712 USA.
authors.forename: Seung-Min
authors.initials: SM
authors.lastname: Oh
authors.affiliation: Materials Science and Engineering Program & Texas Materials Institute The University of Texas at Austin Austin TX 78712 USA.
authors.forename: Wangda
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Energy Engineering School of Energy and Chemical Engineering Ulsan National Institute of Science and Technology (UNIST) 689-798 Ulsan South Korea.
authors.forename: Seunjun
authors.initials: S
authors.lastname: Myeong
authors.affiliation: Department of Energy Engineering School of Energy and Chemical Engineering Ulsan National Institute of Science and Technology (UNIST) 689-798 Ulsan South Korea.
authors.forename: Jaephil
authors.initials: J
authors.lastname: Cho
authors.affiliation: Materials Science and Engineering Program & Texas Materials Institute The University of Texas at Austin Austin TX 78712 USA.
authors.forename: Arumugam
authors.initials: A
authors.lastname: Manthiram
keywords: chemical activation; heterostructure; lithium‐rich layered oxide; nickel‐rich layered oxide; surface stabilization