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ACS Nano. 2019 Sep 16. doi: 10.1021/acsnano.9b05580. [Epub ahead of print]

Multiple Anionic Transition-Metal Oxycarbide for Better Lithium Storage and Facilitated Multielectron Reactions.

Author information

1
Faculty of Materials Science and Chemical Engineering , Ningbo University , Ningbo 315211 , China.
2
College of Automotive and Mechanical Engineering , Changsha University of Science and Technology , Changsha 410015 , China.
3
College of Chemistry and Materials Science , South-Central University for Nationalities , Wuhan 430074 , China.
4
School of Materials Science and Engineering , University of New South Wales , Sydney 2052 , Australia.
5
Department of Materials Science , Fudan University , Shanghai 200433 , China.

Abstract

As an important class of multielectron reaction materials, the applications of transition-metal oxides (TMOs) are impeded by volume expansion and poor electrochemical activity. To address these intrinsic limitations, the renewal of TMOs inspires research on incorporating an advanced interface layer with multiple anionic characteristics, which may add functionality to support properties inaccessible to a single-anion TMO electrode. Herein, a transition-metal oxycarbide (TMOC, M = Mo) with more than one anionic species was prepared as an interface layer on a corresponding oxide. A multiple anionic TMOC possesses advantages of structural stability, abundant active sites, and elevated metal cation valence states. Such merits mitigate volume changes and enhance multielectron reactions significantly. The TMOC nanocomposite has a well-maintained capacity after 1000 cycles at 2 A·g-1 and fully resumed rate performance. In situ synchrotron X-ray powder diffraction (SXRPD) analysis unveils negligible volume expansions occurring upon oxycarbide layer coupling, with lattice spacing variation less than 1% during cycling. The lithium storage mechanism is further inspected by combined analysis of kinetics, SXRPD, and first-principles calculations. Superior to TMO, multielectron reactions of the TMOC electrode have been boosted due to easier rupture of the metal-oxygen bond. Such improvements underscore the importance of incorporating an oxycarbide configuration as a strategy to expand applications of TMOs.

KEYWORDS:

anion-centered chemistry; interface integrations; lithium ion batteries; multielectron reactions; oxycarbide configurations

PMID:
31508937
DOI:
10.1021/acsnano.9b05580

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