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Ti‐Gradient Doping to Stabilize Layered Surface Structure for High Performance High‐Ni Oxide Cathode of Li‐Ion Battery

Ti‐Gradient Doping to Stabilize Layered Surface Structure for High Performance High‐Ni Oxide... High‐Ni layered oxide cathodes are considered to be one of the most promising cathodes for high‐energy‐density lithium‐ion batteries due to their high capacity and low cost. However, surfice residues, such as NiO‐type rock‐salt phase and Li2CO3, are often formed at the particle surface due to the high reactivity of Ni3+, and inevitably result in an inferior electrochemical performance, hindering the practical application. Herein, unprecedentedly clean surfaces without any surfice residues are obtained in a representative LiNi0.8Co0.2O2 cathode by Ti‐gradient doping. High‐resolution transmission electron microscopy (TEM) reveals that the particle surface is composed of a disordered layered phase (≈6 nm in thickness) with the same rhombohedra structure as its interior. The formation of this disordered layered phase at the particle surface is electrochemically favored. It leads to the highest rate capacity ever reported and a superior cycling stability. First‐principles calculations further confirm that the excellent electrochemical performance has roots in the excellent chemical/structural stability of such a disordered layered structure, mainly arising from the improved robustness of the oxygen framework by Ti doping. This strategy of constructing the disordered layered phase at the particle surface could be extended to other high‐Ni layered transition metal oxides, which will contribute to the enhancement of their electrochemical performance. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Advanced Energy Materials Wiley

Ti‐Gradient Doping to Stabilize Layered Surface Structure for High Performance High‐Ni Oxide Cathode of Li‐Ion Battery

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References (47)

Publisher
Wiley
Copyright
© 2019 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim
ISSN
1614-6832
eISSN
1614-6840
DOI
10.1002/aenm.201901756
Publisher site
See Article on Publisher Site

Abstract

High‐Ni layered oxide cathodes are considered to be one of the most promising cathodes for high‐energy‐density lithium‐ion batteries due to their high capacity and low cost. However, surfice residues, such as NiO‐type rock‐salt phase and Li2CO3, are often formed at the particle surface due to the high reactivity of Ni3+, and inevitably result in an inferior electrochemical performance, hindering the practical application. Herein, unprecedentedly clean surfaces without any surfice residues are obtained in a representative LiNi0.8Co0.2O2 cathode by Ti‐gradient doping. High‐resolution transmission electron microscopy (TEM) reveals that the particle surface is composed of a disordered layered phase (≈6 nm in thickness) with the same rhombohedra structure as its interior. The formation of this disordered layered phase at the particle surface is electrochemically favored. It leads to the highest rate capacity ever reported and a superior cycling stability. First‐principles calculations further confirm that the excellent electrochemical performance has roots in the excellent chemical/structural stability of such a disordered layered structure, mainly arising from the improved robustness of the oxygen framework by Ti doping. This strategy of constructing the disordered layered phase at the particle surface could be extended to other high‐Ni layered transition metal oxides, which will contribute to the enhancement of their electrochemical performance.

Journal

Advanced Energy MaterialsWiley

Published: Nov 1, 2019

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