Structural and electrochemical study of fast Li diffusion in Li3V2(PO4)3-based electrode materialстатья
Статья опубликована в высокорейтинговом журнале
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 25 апреля 2017 г.
Аннотация:NASICON-type lithium-vanadium phosphate (Li3V2(PO4)3) based electrodes capable to provide
extremely fast lithium transport properties were studied by a combination of structure, morphology
and surface characterization methods: X-ray diffraction (XRD), scanning electron microscopy (SEM),
Brunauer-Emmett-Teller (BET), laser diffraction particle size distribution (PSD), as well as electrochemi-
cal methods: potentiostatic (PITT) and galvanostatic (GITT) intermittent titration techniques,
electrochemical impedance spectroscopy (EIS), and constant current chronopotentiometry. Significant
differences in the kinetics of reversible lithium intercalation depending on the lithiation stage were
found: lithium diffusion coefficients, found from the PITT, GITT and EIS data, demonstrate an abrupt drop
by 2–3 orders of magnitude in the 4.3–4.4 V potential range vs Li/Li+, which is
attributed to the LiV2(PO4)3 - V2(PO4)3 phase transition. The electrochemical extraction/insertion of two
lithium equivalents can occur at ultra-high rates (up to 320C) from/into structurally more accessible Li2
and Li3 sites, while the de/intercalation of the third lithium equivalent from/into the Li1 position is
supposedly hindered kinetically. To analyze the electrochemical data, specially developed theoretical
models were used, which take into account geometry and phase configuration of the diffusion space, as
well as the properties of the phase boundary interfaces. Morphology and size distribution parameters,
essential for mathematical processing of the electrochemical data, were obtained by SEM, PSD and BET
methods.