Elucidating the Role of Defects for Electrochemical Intercalation in Sodium Vanadium Oxide

Autor:	Pei Yi, Evan Uchaker, Hongyun Jin, Guozhong Cao
Rok vydání:	2015
Předmět:	General Chemical Engineering Sodium Inorganic chemistry Oxalic acid chemistry.chemical_element General Chemistry Electrochemistry Oxygen Vanadium oxide law.invention chemistry.chemical_compound chemistry Transition metal law Materials Chemistry Calcination Stoichiometry
Zdroj:	Chemistry of Materials. 27:7082-7090
ISSN:	1520-5002 0897-4756
DOI:	10.1021/acs.chemmater.5b02935
Popis:	Na1.25+xV3O8 (with x 0) was synthesized via a wet chemical route involving the reduction of V2O5 in oxalic acid and NaNO3 followed by calcination. It was possible to control the sodium composition in the final product by adjusting the amount of sodium precursor added during synthesis. It was revealed that deficient and excessive sodium contents, with respect to the ideal stoichiometry, are accommodated or compensated by the respective generation of oxygen vacancies and partial transition metal reduction, or cation disordering. When examined as NIB electrode material, the superior performance of the cation disordered material with excessive sodium was clearly demonstrated, with more than 50% higher storage capacity and superior rate capacity and cyclic stability. The formation of oxygen vacancies initially seemed promising but was coupled with stability issues and capacity fading upon further cycling. The disparity in electrochemical performance was attributed to variations in the electroni...
Databáze:	OpenAIRE
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