Direct synthesis of nanocrystalline Li0.90FePO4: observation of phase segregation of anti-site defects on delithiation

Shri-Prakash Badi, Marnix Wagemaker, Brian L. Ellis, Deepak P. Singh, Wouter J.H. Borghols, Wang Hay Kan, D. H. Ryan, Fokko M. Mulder, Linda F. Nazar

Research output: Contribution to journalArticleAcademicpeer-review

45 Citations (Scopus)

Abstract

Solid solutions of LixFePO4 are of tremendous interest because of a proposed increase in ion transport properties, but the formation of these solutions at high temperatures is difficult if not impossible and direct synthesis is difficult and rarely reported. Here we report modified polyol syntheses which produce nanocrystalline Li1-yFePO4 directly, where the maximum Li substoichiometry on the M1 site sustained at synthesis temperatures of 320 [degree]C is about 10%. High target lithium vacancy concentrations promote the increase in anti-site disorder of Li+ and Fe2+, as this process is driven by vacancy stabilization. Combined neutron and X-ray diffraction on partial delithiated substoichiometric olivines reveals segregated defect-free (where Li is extracted) and defect-ridden (where Li remains) regions. This proves (1) that the anti-site defects obstruct Li+ diffusion explaining the detrimental electrochemistry and (2) that the anti-site defects form clusters. Finally, preferential anisotropic strain broadening in the bc-plane indicates the existence of a coherent interface between the Li-poor and Li-rich phases. Along with the size broadening upon delithiation this proves that in nano-sized LixFePO4 the two phases coexist within a single particle, which is not expected based on thermodynamics arguments due to the energy penalty associated with the coherent interface. Thereby, these results give important and unique insight and understanding in the properties of nano sized LiFePO4.
Original languageEnglish
Pages (from-to)10085-10093
Number of pages9
JournalJournal of materials chemistry
Volume21
Issue number27
DOIs
Publication statusPublished - 2011
Externally publishedYes

Fingerprint

Defects
Vacancies
Olivine
Polyols
Electrochemistry
Lithium
Transport properties
Solid solutions
Neutrons
Stabilization
Thermodynamics
Ions
X ray diffraction
Temperature
LiFePO4
polyol
olivine

Cite this

Badi, Shri-Prakash ; Wagemaker, Marnix ; Ellis, Brian L. ; Singh, Deepak P. ; Borghols, Wouter J.H. ; Kan, Wang Hay ; Ryan, D. H. ; Mulder, Fokko M. ; Nazar, Linda F. / Direct synthesis of nanocrystalline Li0.90FePO4: observation of phase segregation of anti-site defects on delithiation. In: Journal of materials chemistry. 2011 ; Vol. 21, No. 27. pp. 10085-10093.
@article{8036e688317140b7900b27eb3d7baf69,
title = "Direct synthesis of nanocrystalline Li0.90FePO4: observation of phase segregation of anti-site defects on delithiation",
abstract = "Solid solutions of LixFePO4 are of tremendous interest because of a proposed increase in ion transport properties, but the formation of these solutions at high temperatures is difficult if not impossible and direct synthesis is difficult and rarely reported. Here we report modified polyol syntheses which produce nanocrystalline Li1-yFePO4 directly, where the maximum Li substoichiometry on the M1 site sustained at synthesis temperatures of 320 [degree]C is about 10{\%}. High target lithium vacancy concentrations promote the increase in anti-site disorder of Li+ and Fe2+, as this process is driven by vacancy stabilization. Combined neutron and X-ray diffraction on partial delithiated substoichiometric olivines reveals segregated defect-free (where Li is extracted) and defect-ridden (where Li remains) regions. This proves (1) that the anti-site defects obstruct Li+ diffusion explaining the detrimental electrochemistry and (2) that the anti-site defects form clusters. Finally, preferential anisotropic strain broadening in the bc-plane indicates the existence of a coherent interface between the Li-poor and Li-rich phases. Along with the size broadening upon delithiation this proves that in nano-sized LixFePO4 the two phases coexist within a single particle, which is not expected based on thermodynamics arguments due to the energy penalty associated with the coherent interface. Thereby, these results give important and unique insight and understanding in the properties of nano sized LiFePO4.",
author = "Shri-Prakash Badi and Marnix Wagemaker and Ellis, {Brian L.} and Singh, {Deepak P.} and Borghols, {Wouter J.H.} and Kan, {Wang Hay} and Ryan, {D. H.} and Mulder, {Fokko M.} and Nazar, {Linda F.}",
year = "2011",
doi = "10.1039/C0JM04378H",
language = "English",
volume = "21",
pages = "10085--10093",
journal = "Journal of materials chemistry",
issn = "0959-9428",
publisher = "Royal Society of Chemistry",
number = "27",

}

Badi, S-P, Wagemaker, M, Ellis, BL, Singh, DP, Borghols, WJH, Kan, WH, Ryan, DH, Mulder, FM & Nazar, LF 2011, 'Direct synthesis of nanocrystalline Li0.90FePO4: observation of phase segregation of anti-site defects on delithiation' Journal of materials chemistry, vol. 21, no. 27, pp. 10085-10093. https://doi.org/10.1039/C0JM04378H

Direct synthesis of nanocrystalline Li0.90FePO4: observation of phase segregation of anti-site defects on delithiation. / Badi, Shri-Prakash; Wagemaker, Marnix; Ellis, Brian L.; Singh, Deepak P.; Borghols, Wouter J.H.; Kan, Wang Hay; Ryan, D. H.; Mulder, Fokko M.; Nazar, Linda F.

In: Journal of materials chemistry, Vol. 21, No. 27, 2011, p. 10085-10093.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Direct synthesis of nanocrystalline Li0.90FePO4: observation of phase segregation of anti-site defects on delithiation

AU - Badi, Shri-Prakash

AU - Wagemaker, Marnix

AU - Ellis, Brian L.

AU - Singh, Deepak P.

AU - Borghols, Wouter J.H.

AU - Kan, Wang Hay

AU - Ryan, D. H.

AU - Mulder, Fokko M.

AU - Nazar, Linda F.

PY - 2011

Y1 - 2011

N2 - Solid solutions of LixFePO4 are of tremendous interest because of a proposed increase in ion transport properties, but the formation of these solutions at high temperatures is difficult if not impossible and direct synthesis is difficult and rarely reported. Here we report modified polyol syntheses which produce nanocrystalline Li1-yFePO4 directly, where the maximum Li substoichiometry on the M1 site sustained at synthesis temperatures of 320 [degree]C is about 10%. High target lithium vacancy concentrations promote the increase in anti-site disorder of Li+ and Fe2+, as this process is driven by vacancy stabilization. Combined neutron and X-ray diffraction on partial delithiated substoichiometric olivines reveals segregated defect-free (where Li is extracted) and defect-ridden (where Li remains) regions. This proves (1) that the anti-site defects obstruct Li+ diffusion explaining the detrimental electrochemistry and (2) that the anti-site defects form clusters. Finally, preferential anisotropic strain broadening in the bc-plane indicates the existence of a coherent interface between the Li-poor and Li-rich phases. Along with the size broadening upon delithiation this proves that in nano-sized LixFePO4 the two phases coexist within a single particle, which is not expected based on thermodynamics arguments due to the energy penalty associated with the coherent interface. Thereby, these results give important and unique insight and understanding in the properties of nano sized LiFePO4.

AB - Solid solutions of LixFePO4 are of tremendous interest because of a proposed increase in ion transport properties, but the formation of these solutions at high temperatures is difficult if not impossible and direct synthesis is difficult and rarely reported. Here we report modified polyol syntheses which produce nanocrystalline Li1-yFePO4 directly, where the maximum Li substoichiometry on the M1 site sustained at synthesis temperatures of 320 [degree]C is about 10%. High target lithium vacancy concentrations promote the increase in anti-site disorder of Li+ and Fe2+, as this process is driven by vacancy stabilization. Combined neutron and X-ray diffraction on partial delithiated substoichiometric olivines reveals segregated defect-free (where Li is extracted) and defect-ridden (where Li remains) regions. This proves (1) that the anti-site defects obstruct Li+ diffusion explaining the detrimental electrochemistry and (2) that the anti-site defects form clusters. Finally, preferential anisotropic strain broadening in the bc-plane indicates the existence of a coherent interface between the Li-poor and Li-rich phases. Along with the size broadening upon delithiation this proves that in nano-sized LixFePO4 the two phases coexist within a single particle, which is not expected based on thermodynamics arguments due to the energy penalty associated with the coherent interface. Thereby, these results give important and unique insight and understanding in the properties of nano sized LiFePO4.

U2 - 10.1039/C0JM04378H

DO - 10.1039/C0JM04378H

M3 - Article

VL - 21

SP - 10085

EP - 10093

JO - Journal of materials chemistry

JF - Journal of materials chemistry

SN - 0959-9428

IS - 27

ER -