Crystallinity of nano C-LiFePO4 prepared by the polyol process

Azib, Tahar; Ammar, Souad; Nowak, Sophie; Lau-Truing, S.; Groult, Henri; Zaghib, Karim; Mauger, A.; Julien, C.

doi:10.1016/j.jpowsour.2012.05.106

Cited by 29 publications

(19 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The interdependence between crystallinity and magnetic properties has been already studied in different homogeneous systems . This effect has been ignored in magnetically contrasted heterogeneous structures.…”

Section: Resultsmentioning

confidence: 98%

Magnetic Traits in CoO‐Core@CoFe₂O₄‐shell Like Nanoparticles

et al. 2019

View full text Add to dashboard Cite

Antiferromagnetic (AF) CoO pseudo-single crystals 125 AE 20 nm in diameter were prepared by forced hydrolysis in polyol and used as seeds to grow a poly-and nanocrystalline (5 nm in diameter) ferrimagnetic (F) CoFe 2 O 4 shell. Transmission electron microscopy (TEM) showed a certain epitaxy between the face-centered cubic lattices of the AF rock-salt core and the F spinel shell. Magnetometry measurements do not evidence any exchange bias feature between the two phases in direct contact. The hysteresis loops recorded between 7 and À7 T after cooling the composite particles from 400 K (between the Néel and the Curie temperatures of the AF and F phases, respectively) to 5 K, with and without a cooling magnetic field (m 0 H FC = +7 T), are the same, meaning that the AF core does not allow any spin pinning on the CoFe 2 O 4 nanocrystals. Nevertheless, differences exist between these magnetic data and those collected on two CoFe 2 O 4 reference particles: the low temperature coercive field of the composite is between those of 5 nm sized single-crystals and their assembly as submicrometer polycrystals. This order was also observed for the blocking temperature, although the constituting CoFe 2 O 4 nanocrystals of all these particles, the composite and the two references, were the same. Advanced analysis by X-ray diffraction and TEM established that the coherent crystallographic domain length of the ferrite phase and the magnetic behavior of the three systems are interdependent. Depending on the growth conditions of the CoFe 2 O 4 phase, a relative epitaxy between the nanocrystals may exist. It is much greater in the polycrystalline CoFe 2 O 4 particles than in their CoOÀCoFe 2 O 4 core-shell counterparts, and does not occur in free single crystal CoFe 2 O 4 particles.[a] Dr.

show abstract

Section: Resultsmentioning

confidence: 98%

Magnetic Traits in CoO‐Core@CoFe₂O₄‐shell Like Nanoparticles

et al. 2019

View full text Add to dashboard Cite

show abstract

“…The wet-chemical techniques could be classified in four groups according the salts and complexing agent used (Table 12.1). They are namely sol-gel [9,10], co-precipitation [11,12], combustion [13], pyrolysis [14], polyol [15], Pechini process [16,17], etc. ; they were employed for the preparation of nanostructured metal oxides devoted to electrodes for Li-ion batteries.…”

Section: Wet-chemical Methodsmentioning

confidence: 99%

Nanotechnology for Energy Storage

et al. 2016

View full text Add to dashboard Cite

Nanomaterials of metal oxides have been intensively studied as anode and cathode materials for lithium-ion batteries (LiBs) aimed at achieving higher specific capacities and high power density. It is worth pointing out that the word "nanotechnology" has become very popular and is used to describe many types of research where the characteristic dimensions are much less than 1 μm. For example, continued improvements in lithography to design computer components have resulted in line widths that are less than one micron: this work is often called "nanotechnology." Many of the exponentially improving trends in computer hardware capability have remained steady for the last 50 years. Today "nanosciences" are fairly widespread with the belief that these trends are likely to continue for at least several years; however, new aspects are now considered in the field of energy transformation. In this respect, the classic 1959 article "There's plenty of room at the bottom" by Richard P. Feynman discusses the limits of miniaturization and forecast the ability to ". . .arrange the atoms the way we want; the very atoms, all the way down!" [1]. Nano-structured materials are distinguished from conventional polycrystalline materials by the size of the structural entities that comprises them, microstructures comprising nanoscale domains in at least one dimension. The ability to control a material's structure and composition at the nano-level has demonstrated that materials and devices having properties intrinsically different from their polycrystalline counterparts can be fabricated. As tailoring of fundamental properties becomes possible at the atomic level, the prospect of developing novel materials and devices with new applications become viable.Conventional rechargeable Li batteries exhibit rather poor rate performance, even compared with old technologies such as lead-acid [2]. Achieving high rate rechargeable Li-ion batteries depends ultimately of the dimension of the active particles for both negative and positive electrodes. One of the prospective solutions for the preparation of electrodes with high power density is the choice of

show abstract

“…The conventional hydrothermal process involves a reaction time 5-12 h to synthesize LFP [40,41]. With respect to the previous techniques, the hydrothermal process has the advantage that the synthesis temperature can be as small as 230°C [42].…”

Section: Synthesis Routesmentioning

confidence: 99%

“…Bigger particles can be obtained by the solvothermal process in a polyol medium of diethylene glycol, but still under the form of plates or rods. The advantage of this process is that the polyol medium acts not only as a solvent, but also as a reducing agent and stabilizer that limits the particle growth and prevents agglomeration [38][39][40]. In general, the solvothermal process leads to the formation of LFP under the form of plates, about 50 nm-thick [41], which can be self-assembled by using poly(vinyl pyrrolidone) (PVP) as the surfactant in a benzyl alcohol system [42].…”

Section: Synthesis Routesmentioning

confidence: 99%