resumo
Existence of defects is an inherent property of real materials. Due to an explicit correlation between defects concentration and conductivity, it is important to understand the level and origins of the structural heterogeneity for any particulate electrode material. Poor conductive lithium titanate Li4Ti5O12 (LTO), widely used in batteries for grids and electric buses, needs it like no one else. In this work, structural heterogeneity of compacted lithium titanate is measured locally in 100 different points by conventional micro-Raman technique, characterized in terms of variation of Raman spectra parameters and interpreted using our version of "big data" analysis. This very simple approach with automated measurement and treatment has allowed us to demonstrate inherent heterogeneity of solid-state synthesized LTO and attribute it to the existence of lithium and oxygen vacancies. The proposed approach can be used as a fast, convenient, and cost-effective defects-probing tool for a wide range of materials with defects-sensitive properties. In case of LTO, such an approach can be used to increase its charge/discharge rates by synthesis of materials with controlled nonstoichiometry. New approaches to solid state synthesis of LTO, suitable for high-power applications, will help to significantly reduce the costs of batteries for heavy-duty electric vehicles and smart-grids. (C) 2017 Elsevier B.V. All rights reserved.
palavras-chave
LI-ION BATTERIES; ELECTROCHEMICAL PROPERTIES; NEGATIVE ELECTRODE; OXYGEN VACANCIES; SPINEL LI4TI5O12; TITANIUM-SPINEL; RATE-CAPABILITY; CYCLE LIFE; PERFORMANCE; ANODE
categoria
Chemistry; Electrochemistry; Energy & Fuels; Materials Science
autores
Pelegov, DV; Slautin, BN; Gorshkov, VS; Zelenovskiy, PS; Kiselev, EA; Kholkin, AL; Shur, VY
nossos autores
Andrei Kholkin
Investigador Principal
Pavel Zelenovskii
InvestigadorGrupos
G2 - Materiais Fotónicos, Eletrónicos e Magnéticos
G3 - Materiais Eletroquímicos, Interfaces e Revestimentos
agradecimentos
The authors thank E.V. Antipov (MSU), I.A. Leonidov (ISSC UB RAS), and E.L. Rumyantsev (UrFU) for fruitful discussions, D.K. Kuznetsov (UrFU) for SEM images in SM and A.S. Krylov (KIP SB RAS) for help with automated Raman spectra treatment. The equipment of the Ural Center for Shared Use "Modern nanotechnology" UrFU was used. The work was supported by Government of the Russian Federation (Act 211, Agreement 02.A03.21.0006). V.Ya. Shur acknowledges financial support within the State Task from the Ministry of Education and Science of Russian Federation (Project No.1366.2014/236). A.L. Kholkin thanks Portuguese Foundation for Science and Technology (FCT) for the financial support (grant #PTDC/CTM-ENE/6341/2014). Part of this work was developed in the scope of the project CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (Ref. FCT UID/CTM/50011/2013), financed by national funds through the FCT/MEC and when applicable co-financed by FEDER under the PT2020 Partnership Agreement.