Lithium, Iron, and Phosphate precursors were used for the synthesis of LiFePO4 by Hydro-thermal synthesis route. The XRD data of the sample shows peaks (2 theta angles) which are completely different than JCPDS data. As i am getting too many peaks in XRD, what is meaning of it? Whether this structure is amorphous or Crystalline?
If it is crystalline how can i conform its structural phase? Which peaks (All peaks or only of relative high intensity) should i use to interpret the data? how to find structural phase of the crystal structure from XRD data.
XRD data of the material is attached herewith.
First of all, you should mention at which wavelength this data was measured. Is it measured at Cu K alpha wavelength?
Cu / 40 kV / 40 mA
Filter : K-beta filter
Goniometer : Ultima IV
It might possible that your precursors have not reacted properly. You should try to find out possibility of formation of others oxides like LiPO4, FePO4, by matching your XRD data with XRD pattern of these materials.
Agree!
Can you reply for below mentioned question.
As i am getting too many peaks in XRD, what is meaning of it? Whether this structure is amorphous or Crystalline?
If it is crystalline how can i conform its structural phase? Which peaks (All peaks or only of relative high intensity) should i use to interpret the data?
First of all I would try to improve the data quality, your data is too noisy to decide for the presence or non-presence of certain phases. Please increase your data collection time or do multiple measurements and add those up.
I tried to identify some phases but due to the low data quality this isn't conclusive
You can't draw conclusions yet, you need to improve your counting statistics (data quality) first.
Right now you can not decide what is a real peak and what is just a noise peak.
And yes, based on the amount and shape of the background intensity you also have amorphous compound(s) in your sample.
I agree with Thomas Degan Sir. Data quality is not good enough to ensure which peaks are due to sample or are they just background contribution.
Dear Chetan,
first of all, check how the purity of all reactants is in your initial mixture.
Using hydrothermal reaction, the crystallinity of your material will, in general case, be less crystalline, the nucleation is so fast, that hardly good large crystals are going to form. Be sure you don't face phase speciation.
Using search program like Match, Crystallographica among others, firstly try to identify residue from your reactants. If present, you need to change your syntheses pathways or physical conditions at all.
In case you don't have your reactants, check the presence of your interest compound, by comparing the observed diffraction with the Bragg position reflections of the phase you need. In some cases you may not have the desirable materials as a product, having formed not important other phases.
By inspecting your X-ray diffraction, is easy to see that your material has a significant amount of amorphous phase, the time constant from your measuring setup was inadequate, the fluctuation of your baseline (background) is so significant when compared with your peak intensity, please increase the counting time. You need to reconsider the syntheses setup, especially if the reflection peaks didn't correspond to the desired phase.
If you have what you like, from now on, you can extract the intensities using let say Fullprof profile using Pawley or Lebail extraction routine.
At this point, you have the unit cell almost full characterized by a, b, c, alfa, beta and gamma parameters — this point forward to use Rietveld fitting routine to adjust your theoretical structure model to the measured one. Now you have characterized in full way the phase or phases and have if more than one, one idea of the relative amount each other.
best regards
WNM
If you do multiple measurements with XRD analysis and your result is still the same (produce amorphous phases and causes low intensities), you should check your experimental method.
Here is a method may help you, https://www.researchgate.net/publication/339363196_Match_XRD_data_with_JCPDS-_A_method_2020/stats
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