Chanaiporn Danvirutai

Bio: Chanaiporn Danvirutai is an academic researcher from Khon Kaen University. The author has contributed to research in topics: Thermal decomposition & Differential thermal analysis. The author has an hindex of 15, co-authored 41 publications receiving 566 citations.

Determination of kinetic triplet of the synthesized Ni 3 (PO 4 ) 2 ·8H 2 O by non-isothermal and isothermal kinetic methods

Abstract: The nickel phosphate octahydrate (Ni3(PO4)2·8H2O) was synthesized by a simple procedure and characterized by FTIR, TG/DTG/DTA, AAS, and XRD techniques. The morphologies of the title compound and its decomposition product were studied by the SEM method. The dehydration process of the synthesized hydrate occurred in one step over the temperature range of 120–250 °C, and the thermal decomposition product at 800 °C was found to be Ni3(PO4)2. The kinetic parameters (E and A) of this step were calculated using the Ozawa–Flynn–Wall and Kissinger–Akahira–Sunose methods. The iterative methods of both equations were carried out to determine the exact values of E, which confirm the single-step mechanism of the dehydration process. The non-isothermal kinetic method was used to determine the mechanism function of the dehydration, which indicates the contracting disk mechanism of R1 model as the most probable mechanism function and agrees well with the isothermal data. Besides, the isokinetic temperature value (Ti) was calculated from the spectroscopic data. The thermodynamic functions of the activated complex (ΔS≠, ΔH≠, and ΔG≠) of the dehydration process were calculated using the activated complex theory of Eyring. The kinetic parameters and thermodynamic functions of the activated complex for the dehydration process of Ni3(PO4)2·8H2O are reported for the first time.

Micrometer‐Sized, Nanoporous, High‐Volumetric‐Capacity LiMn0.85Fe0.15PO4 Cathode Material for Rechargeable Lithium‐Ion Batteries

Abstract: Since their introduction by Sony in 1991, rechargeable lithiumion batteries have relied on lithium transition metal oxides as the main sources of cathode active materials. However, these materials suffer by the intrinsic disadvantage of a poor thermal stability due to release of oxygen from the highly delithiated oxide materials. [ 1 ] For this reason, olivine-type LiMPO 4 (M = Fe, Mn, Co, and Ni) compounds which possess a high thermal stability, superior safety properties, and an excellent cycle life, are promising alternative cathode materials especially for large-scale batteries designed for applications in electric vehicles (EVs) or in renewable energy storage plants. [ 2–4 ] Low price, non-toxicity, and environmental friendliness are other important properties of these attractive electrodes. However, LiMPO 4 materials have an intrinsically poor electrical and ionic conductivity, this affecting their electrochemical performance. [ 5 ] In the case of M = Fe, i.e. of LiFePO 4 , the poor conductivity issue has been successfully overcome by fabricating it in the form of nanometer-sized particles coated by a thin conductive carbon layer. [ 6–12 ] The carbon-coated, nanoscale LiFePO 4 electrode has demonstrated more than 90% of the theoretical capacity and an excellent rate capability. Hence, LiFePO 4 has established its position as one of the most promising cathode materials for highperformance lithium-ion batteries. The interest in olivine electrodes, already established by the success of LiFePO 4, may fi nd an additional impulse by moving to the manganese member of the family, LiMnPO 4 . This material is in fact of great interest, because its Mn 2 + /Mn 3 + redox potential is higher than that of the Fe 2 + /Fe 3 + redox potential, i.e., 4.1 V versus Li/Li + compared to 3.4 V versus Li/Li + . However, also LiMnPO 4 suffers from poor electrochemical performance, especially at higher current densities, due to its inherently low electronic and ionic conductivities caused by heavy polaronic holes localized on the Mn 3 + sites and by the s train

From molecules to materials: Molecular paddle-wheel synthons of macromolecules, cage compounds and metal–organic frameworks

Abstract: Metal–organic frameworks (MOF) are becoming a more and more important class of functional materials. Yet, very often, the synthesis of MOFs is not easy to control and requires a profound knowledge and experience in solid state chemistry. One of the most frequently used metal connectors is the so-called ‘paddle-wheel’ (PW) unit, which is a well-known molecular compound type in inorganic coordination chemistry. Depending on the ligands, the geometry of PWs strictly directs the assembly of ordered networks. This review focuses on the question, to what extent ordered network structures can be accessed by typical molecular syntheses in solution, starting from molecular PW complexes to ordered macromolecules, finite cage compounds and finally, three-dimensional superstructures.