Structure and Stability of Olivine Phase FePO4

2011 ◽  
Vol 1333 ◽  
Author(s):  
Gene M. Nolis ◽  
Natalya A. Chernova ◽  
Shailesh Upreti ◽  
M. Stanley Whittingham

ABSTRACTLiFePO4 has shown considerable promise as a cathode material in Li-ion batteries due to its stability, low toxicity and high cyclability. However, the data on thermodynamic stability of olivine phase FePO4 (o-FePO4), the delithiated form of o-LiFePO4, remains scarce and contradictory. In this work, o-FePO4 was synthesized by chemical delithiation of o-LiFePO4 and characterized structurally and thermally. X-ray diffraction and absorption data indicate pure olivine phase, but with residual amount of Fe2+, most likely due to incomplete delithiation. Differential scanning calorimetry and thermal gravimetric analysis reveal that o-LixFePO4 decomposes exothermally above 550 °C with about 9% weight loss, the products being trigonal phase FePO4, Fe7(PO4)6, and LiPO3.

Author(s):  
Partha P. Paul ◽  
Chuntian Cao ◽  
Vivek Thampy ◽  
Hans-Georg Steinrück ◽  
Tanvir R. Tanim ◽  
...  

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2457 ◽  
Author(s):  
Haifeng Zhao ◽  
Jing Lv ◽  
Junshan Sang ◽  
Li Zhu ◽  
Peng Zheng ◽  
...  

In this work, a mixing-calcination method was developed to facilely construct MXene/CuO nanocomposite. CuO and MXene were first dispersed in ethanol with sufficient mixing. After solvent evaporation, the dried mixture was calcinated under argon to produce a MXene/CuO nanocomposite. As characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and X-ray photoelectron spectra (XPS), CuO nanoparticles (60–100 nm) were uniformly distributed on the surface and edge of MXene nanosheets. Furthermore, as evaluated by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA), the high-temperature decomposition (HTD) temperature decrease of ammonium perchlorate (AP) upon addition of 1 wt% CuO (hybridized with 1 wt% MXene) was comparable with that of 2 wt% CuO alone, suggesting an enhanced catalytic activity of CuO on thermal decomposition of AP upon hybridization with MXene nanosheets. This strategy could be further applied to construct other MXene/transition metal oxide (MXene/TMO) composites with improved performance for various applications.


2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Rai Muhammad Sarfraz ◽  
Muhammad Rouf Akram ◽  
Muhammad Rizwan Ali ◽  
Asif Mahmood ◽  
Muhammad Usman Khan ◽  
...  

Current research work was carried out for gastro-protective delivery of naproxen sodium. Polyethylene glycol-g-poly (methacrylic acid) nanogels was developed through free radical polymerization technique. Formulation was characterized for swelling behaviour, entrapment efficiency, Fourier transform infrared (FTIR) spectroscopy, Differential scanning calorimetry (DSC), and Thermal Gravimetric Analysis (TGA), Powder X-ray diffraction (PXRD), Zeta size distribution, and Zeta potential measurements, and in-vitro drug release. pH dependent swelling was observed with maximum drug release at higher pH. PXRD studies confirmed the conversion of loaded drug from crystalline to amorphous form while Zeta size measurement showed size reduction. On the basis of these results it was concluded that prepared nanogels proved an effective tool for gastro-protective delivery of naproxen sodium.


ChemSusChem ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 2240-2250 ◽  
Author(s):  
Lea de Biasi ◽  
Alexander Schiele ◽  
Maria Roca‐Ayats ◽  
Grecia Garcia ◽  
Torsten Brezesinski ◽  
...  

2019 ◽  
Vol 11 (34) ◽  
pp. 30719-30727 ◽  
Author(s):  
Selvamani Vadivel ◽  
Nutthaphon Phattharasupakun ◽  
Juthaporn Wutthiprom ◽  
Salatan duangdangchote ◽  
Montree Sawangphruk

2015 ◽  
Vol 1112 ◽  
pp. 489-492
Author(s):  
Ali Mufid ◽  
M. Zainuri

This research aims to form particles of hematite (α-Fe2O3) with a basis of mineral iron ore Fe3O4 from Tanah Laut. Magnetite Fe3O4 was synthesized using co-precipitation method. Further characterization using X-ray fluorescence (XRF) to obtain the percentage of the elements, obtained an iron content of 98.51%. Then characterized using thermo-gravimetric analysis and differential scanning calorimetry (TGA-DSC) to determine the calcination temperature, that at a temperature of 445 °C mass decreased by 0.369% due to increase in temperature. Further Characterization of X-ray diffraction (XRD) to determine the phases formed at the calcination temperature variation of 400 °C, 445 °C, 500 °C and 600 °C with a holding time of 5 hours to form a single phase α-Fe2O3 hematite. Testing with a particle size analyzer (PSA) to determine the particle size distribution, where test results indicate that the α-Fe2O3 phase of each having a particle size of 269.7 nm, 332.2 nm, 357.9 nm, 412.2 nm. The best quantity is shown at a temperature of 500 °C to form the hematite phase. This result is used as the calcination procedure to obtain a source of Fe ions in the manufacture of Lithium Ferro Phosphate.


2010 ◽  
Vol 25 (8) ◽  
pp. 1601-1616 ◽  
Author(s):  
Jordi Cabana ◽  
Christopher S. Johnson ◽  
Xiao-Qing Yang ◽  
Kyung-Yoon Chung ◽  
Won-Sub Yoon ◽  
...  

The complexity of layered-spinel yLi2MnO3·(1 – y)Li1+xMn2–xO4 (Li:Mn = 1.2:1; 0 ≤ x ≤ 0.33; y ≥ 0.45) composites synthesized at different temperatures has been investigated by a combination of x-ray diffraction (XRD), x-ray absorption spectroscopy (XAS), and nuclear magnetic resonance (NMR). While the layered component does not change substantially between samples, an evolution of the spinel component from a high to a low lithium excess phase has been traced with temperature by comparing with data for pure Li1+xMn2–xO4. The changes that occur to the structure of the spinel component and to the average oxidation state of the manganese ions within the composite structure as lithium is electrochemically removed in a battery have been monitored using these techniques, in some cases in situ. Our 6Li NMR results constitute the first direct observation of lithium removal from Li2MnO3 and the formation of LiMnO2 upon lithium reinsertion.


2014 ◽  
Vol 895 ◽  
pp. 334-337
Author(s):  
Azira Azahidi ◽  
Norlida Kamarulzaman ◽  
Kelimah Elong ◽  
Nurhanna Badar ◽  
Nurul Atikah Mohd Mokhtar

LiCoO2 is a well-known cathode material used in commercial Li-ion batteries but it has its own limitations in terms of cost and toxicity. Improvement of the material by partial substitution of Co with other transition metals is one of the alternative and effective ways to overcome the limitations and improve the electrochemical performance of cathode materials. The transition metal element used for the substitution has to be cheaper and non-toxic thus Mn is chosen here. LiCo(1-x)MnxO2 (x= 0.1, 0.2, 0.3) we synthesized by a novel route using a self-propagating combustion (SPC) method. The samples are analyzed using X-Ray Diffraction (XRD) for phase purity and Field Emission Scanning Electron Microscopy (FESEM) for morphology and particle size studies. The materials obtained are phase pure. In terms of electrochemical activity, though it does not show better first cycle discharge capacity, the Mn doped materials have improved capacity retention. Results showed that LiCo0.9Mn0.1O2 and LiCo0.8Mn0.2O2 exhibited less than 8 % capacity loss in the 20th cycle compared to 12 % for LiCoO2.


2013 ◽  
Vol 4 ◽  
pp. 665-670 ◽  
Author(s):  
Mario Marinaro ◽  
Santhana K Eswara Moorthy ◽  
Jörg Bernhard ◽  
Ludwig Jörissen ◽  
Margret Wohlfahrt-Mehrens ◽  
...  

Aprotic rechargeable Li–O2 batteries are currently receiving considerable interest because they can possibly offer significantly higher energy densities than conventional Li-ion batteries. The electrochemical behavior of Li–O2 batteries containing bis(trifluoromethane)sulfonimide lithium salt (LiTFSI)/tetraglyme electrolyte were investigated by galvanostatic cycling and electrochemical impedance spectroscopy measurements. Ex-situ X-ray diffraction and scanning electron microscopy were used to evaluate the formation/dissolution of Li2O2 particles at the cathode side during the operation of Li–O2 cells.


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