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A Layer‐Structured Electrode Material Reformed by a PO 4 ‐O 2 Hybrid Framework toward Enhanced Lithium Storage and Stability
Author(s) -
Min Sul Hee,
Jo Mi Ru,
Choi SiYoung,
Kim YongIl,
Kang YongMook
Publication year - 2016
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.201501717
Subject(s) - materials science , lithium (medication) , electrolyte , cathode , diffusion , phase (matter) , electrode , chemical engineering , layer (electronics) , ion , nanotechnology , chemistry , thermodynamics , medicine , physics , organic chemistry , quantum mechanics , engineering , endocrinology
The surface framework of LiCoO 2 is modified through a surface treatment called phosphidation, which suppressed the unwanted phase transition occurring above 4.2 V. The surface instability of LiCoO 2 toward organic electrolytes is simultaneously improved by changing its surface structure from an O 2 ‐based framework to a PO 4 ‐based framework that can protect against HF attack during cycling. Phosphidated LiCoO 2 is successfully synthesized that showed greater stability in its bulk and surface structures. The phosphidated form enables faster Li + diffusion and prevents irreversible phase transitions, especially when charged above 4.2 V, and consequently demonstrates excellent cycling performance and rate capabilities. The improved kinetics and stability resulting from phosphidation make LiCoO 2 highly suitable as a high‐voltage cathode material for use in lithium ion batteries.