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One‐Step Synthesis of Highly Oxygen‐Deficient Lithium Titanate Oxide with Conformal Amorphous Carbon Coating as Anode Material for Lithium Ion Batteries
Author(s) -
Nasara Ralph Nicolai,
Tsai Pingchun,
Lin Shihkang
Publication year - 2017
Publication title -
advanced materials interfaces
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.671
H-Index - 65
ISSN - 2196-7350
DOI - 10.1002/admi.201700329
Subject(s) - materials science , faraday efficiency , lithium (medication) , anode , lithium titanate , amorphous solid , chemical engineering , electrochemistry , carbon fibers , titanium , coating , amorphous carbon , nanotechnology , lithium ion battery , electrode , composite material , metallurgy , chemistry , crystallography , battery (electricity) , endocrinology , composite number , engineering , power (physics) , quantum mechanics , medicine , physics
The lithium titanate defect spinel, Li 4 Ti 5 O 12 (LTO), is a promising “zero‐strain” anode material for lithium‐ion batteries in cycling‐demanding applications. However, the low‐rate capability limits its range of applications. Surface modifications, for example, coating and defect engineering, play an intriguing role in interfacial electrochemical processes. Herein, a novel synthesis of highly oxygen‐deficient “defective‐LTO” anode material with high‐rate performance is reported. It is synthesized using conventional precursors via a one‐pot thermal reduction process. A high level of oxygen vacancies of ≈6.5 at% and conformal amorphous carbon coating are achieved simultaneously, resulting in a compounding effect for a high discharge capacity of 123 mAh g −1 with Coulombic efficiency of 99.8% at 10 C‐rate. Ab initio calculations foresight that oxygen vacancies increase the electron donor density of the neighboring titanium atoms, while conformal amorphous carbon significantly lowers interfacial charge‐transfer resistance. The formation mechanism, as well as the origin of enhanced electrochemical properties, is elaborated in this paper.