Studies of selected synthesis procedures of the conducting LiFePO4-based composite cathode materials for Li-ion batteries

Ojczyk, W.; Marzec, J.; Świerczek, Konrad; Zając, Wojciech; Molenda, Marcin; Dziembaj, R.; Molenda, Janina

doi:10.1016/j.jpowsour.2007.05.055

Cited by 58 publications

(38 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…44 The presence of only one doublet assigned to trivalent iron agrees well with the assumption that they substitute vanadium at the 12c octahedral sites of the NASICON structure. Upon charging at 4.3 V, an asymmetric profile is observed, which can be decomposed into a singlet and a doublet, both ascribed to Fe 3+ .…”

supporting

confidence: 75%

Effect of Iron Substitution in the Electrochemical Performance of Na₃V₂(PO₄)₃as Cathode for Na-Ion Batteries

Aragón

Lavela

Ortiz

2015

J. Electrochem. Soc.

152

View full text Add to dashboard Cite

Na 3 V 2-x Fe x (PO 4 ) 3 /C (0 ≤ x ≤ 0.5) samples were prepared by a simple sol-gel method. X-ray diffraction patterns revealed high purity and crystalline phosphate indexed in the R-3c space group. On increasing the iron content, the cell volume increases due to the slightly higher radius of Fe 3+ . Cyclic voltammetry showed two signals at ca. 3.5 and 4.0 V, which evidence a linear dependence of potential on the level of substitution. The appearance of the short plateau at ca. 4.0 V is closely related to the higher iron substitution levels. The evaluation of XPS and 57 Fe Mössbauer spectra of charged and discharged electrodes allow ascribing the 4.0 V plateau to V 4+ /V 5+ redox reaction and the extraction/insertion of extra sodium ions from octahedral M1 sites. Galvanostatic cycling showed capacity values as high as 115 mA h g −1 for samples with x = 0.1, 0. Now that lithium-ion battery (LIB) technology is reaching maturity, a number of reports are advising for the future scarcity of the lithium resources. A full implementation of LIB in the electric vehicle market would involve important constraints on Li production and an undesirable increase of the cost of Li is expected at the long term.1-4 For these reasons, market is alternatively looking forward beyond LIB and new chemistries are being explored. [5][6][7][8] Sodium is an abundant and non-toxic alkali element which can be implemented in insertion based batteries. The electrochemical principles are identical to those of lithium batteries. In fact, a number of recent reports have demonstrated the reliability of sodium batteries to provide reversible energy storage devices. [9][10][11][12] Nevertheless, the larger ionic radius and atomic weight leads to a less performing behavior. Thus, low theoretical capacity and cell voltage, slow diffusion, high unit cell volume change and hence structural impact are detected in electrodes subjected to sodium insertion. Recently, Ceder et al. have reported that the lower voltage for sodium insertion is predominantly a cathodic effect because of the diminished energy gain when inserting this alkaline ion into the host structure. Also, they pointed out to open structures, as layered and NASICON ones, as the most favored frameworks to provide phase stability on cycling. 13 The optimistic arguments promoting these cathode materials are mainly based on an easy transfer reaction of less solvated large ions and high sodium conductivity. 14,15 In this regard, transition metal phosphates with general stoichiometry A x B 2 (PO 4 ) 3 (A: Li + , Na + , etc; B: Fe 3+ , V 3+ , Ti 4+ .) offer a wide compositional variety exhibiting a NASICON-type structure. [16][17][18] Among them, Na 3 V 2 (PO 4 ) 3 has demonstrated interesting properties as a cathode material because of the high operating voltage and good cyclability. [19][20][21][22] Multivalent vanadium atom lends a significant electronic conductivity which promotes the chemical diffusion of sodium ions to this compound. Nevertheless, the electronic conductivity is not high enoug...

show abstract

supporting

confidence: 75%

Effect of Iron Substitution in the Electrochemical Performance of Na₃V₂(PO₄)₃as Cathode for Na-Ion Batteries

Aragón

Lavela

Ortiz

2015

J. Electrochem. Soc.

152

View full text Add to dashboard Cite

show abstract

“…In our case it can be assumed that the oxide layer, resulting from the passivation, prevented the oxidation of the reducing agent with oxygen from air at the intermediate stage of the synthesis, i.e. milling of the mixture after the calcinations at 350°C (Ojczyk et al, 2007). The formation of iron phosphide Fe 2 P resulting from the reduction of phosphate radicals with iron nanoparticles occurs only at higher temperatures (above 600°C).…”

Section: Preparation Of a Composite Phase Lifepo 4 -Fe 2 Pmentioning

confidence: 95%

“…On the basis of the synthesis tests previously performed, we found that the best results were achieved for the reaction mixtures milled in a ball mill. The additional DSC measurements demonstrated that milling the reaction mixture affects the water distribution in the system (Ojczyk et al, 2007). Iron nanoparticles as a reducing agent is highly unstable in the presence of even trace amounts of oxygen.…”

Section: Preparation Of a Composite Phase Lifepo 4 -Fe 2 Pmentioning

confidence: 98%

“…Consequently, the exposure time of the reaction mixture at low temperatures should be as short as possible, therefore high rates of the furnace heating up to the optimum reaction temperature are essential. The results of a thermal analysis for the reaction mixtures yielded a temperature of 800°C for 10 h as the optimum synthesis conditions (Ojczyk et al, 2007). On the basis of the obtained results of thermal analysis and synthetic route trials, it can be concluded that a thin layer of Fe 2 P can be formed only when the appropriate conditions of the synthesis process are satisfied:  The products of the reaction (H 2 O) can be carried away properly from the reactor at the volume flow rate (F v ) of the carrying gas (Ar = 99.999%, O 2 <0.0005%) being at least: F v = 20V react /t for 1 g of the reagents batch where: F v -volume flow rate [cm 3 min -1 ]; V react -the pipe flow reactor volume [cm 3 ]; ttime =60 minutes, both at the initial stage of the decomposition (350°C) and the main hightemperature reaction (800°C),  Linear rate of carrying gas over the reagents should be at least 0.5 cm s -1 ; this would prevent secondary reactions (iron oxidation)  Milling the substrates in a ball mill prior to the reaction ensures an appropriate dispersion of the substrates  A high heating rate ( = 10°min -1 ), ensuring the maximum concentration of the reductive agent at the optimal temperature of the re action (800°C).…”

Section: Preparation Of a Composite Phase Lifepo 4 -Fe 2 Pmentioning

confidence: 99%

“…However, examination of doped phospho-olivine surfaces by J. Molenda et al (Marzec et al, 2006;Ojczyk et al 2007) and the results published by Nazar (Herle et al, 2004) have proved that the high values of conductivity of doped phospho-olivine are not due to bulk metallic properties but due to the formation of metallic iron phosphides on the surface of phospho-olivine grains, which are the effect of partial reduction of LiFePO 4 to Fe 2 P during the synthesis (Fig. 6).…”

Section: Phospho-olivine Lifepomentioning

confidence: 99%

See 2 more Smart Citations

Composite Cathode Material for Li-Ion Batteries Based on LiFePO4 System.

Molenda¹,

Molenda²

2011

Metal, Ceramic and Polymeric Composites for Various Uses

View full text Add to dashboard Cite

Controlled Anisotropic Growth of Co‐Fe‐P from Co‐Fe‐O Nanoparticles

Mendoza‐Garcia

Zhu

et al. 2015

Angewandte Chemie

View full text Add to dashboard Cite

Afacile approach to bimetallic phosphides,Co-Fe-P, by ah igh-temperature (300 8 8C) reaction between Co-Fe-O nanoparticles and trioctylphosphine is presented. The growth of Co-Fe-P from the Co-Fe-O is anisotropic.A saresult, Co-Fe-P nanorods (from the polyhedral Co-Fe-O nanoparticles) and sea-urchin-like Co-Fe-P (from the cubic Co-Fe-O nanoparticles) are synthesized with both the nanorod and the seaurchin-arm dimensions controlled by Co/Feratios.The Co-Fe-Pstructure,especially the sea-urchin-like (Co 0.54 Fe 0.46 ) 2 P, shows enhanced catalysis for the oxygen evolution reaction in KOH with its catalytic efficiency surpassing the commercial Ir catalyst. Our synthesis is simple and may be readily extended to the preparation of other multimetallic phosphides for important catalysis and energy storage applications.

show abstract

Studies of selected synthesis procedures of the conducting LiFePO4-based composite cathode materials for Li-ion batteries

Cited by 58 publications

References 3 publications

Effect of Iron Substitution in the Electrochemical Performance of Na₃V₂(PO₄)₃as Cathode for Na-Ion Batteries

Effect of Iron Substitution in the Electrochemical Performance of Na₃V₂(PO₄)₃as Cathode for Na-Ion Batteries

Composite Cathode Material for Li-Ion Batteries Based on LiFePO4 System.

Controlled Anisotropic Growth of Co‐Fe‐P from Co‐Fe‐O Nanoparticles

Contact Info

Product

Resources

About

Studies of selected synthesis procedures of the conducting LiFePO4-based composite cathode materials for Li-ion batteries

Cited by 58 publications

References 3 publications

Effect of Iron Substitution in the Electrochemical Performance of Na3V2(PO4)3as Cathode for Na-Ion Batteries

Effect of Iron Substitution in the Electrochemical Performance of Na3V2(PO4)3as Cathode for Na-Ion Batteries

Composite Cathode Material for Li-Ion Batteries Based on LiFePO4 System.

Controlled Anisotropic Growth of Co‐Fe‐P from Co‐Fe‐O Nanoparticles

Contact Info

Product

Resources

About

Effect of Iron Substitution in the Electrochemical Performance of Na₃V₂(PO₄)₃as Cathode for Na-Ion Batteries

Effect of Iron Substitution in the Electrochemical Performance of Na₃V₂(PO₄)₃as Cathode for Na-Ion Batteries