Solid-state Combustion Synthesis Research Articles

The solid-state combustion synthesis of in-situ hybrid (Al3Ni+Al2O3)/Al composites and evaluation of its mechanical properties

In-situ hybrid (Al3Ni+Al2O3)/Al composites with bimodal size particles distributions were fabricated via an Al-NiO solid-state combustion reaction and subsequent hot extrusion process. The reaction system between Al and NiO was investigated by differential thermal analysis (DTA). The presence of Al2O3 and Al3Ni in the matrix was verified by XRD/EDS analysis. The in-situ formed Al3Ni phase with varying morphologies and sizes such as particle, plate, strip and flake at different sintering temperatures were observed. And the exothermic reaction of Al-NiO can be reduced to below the melting point of Al, and the desirable sintering temperature was. 600 ℃. In hot-extruded samples, both nano Al2O3 and Al3Ni particles distributed homogeneously, and most of Al3Ni particles is smaller than 2 µm in size. When NiO content increases from 8% to 12%, Al matrix grains in composites can be refined from 1.7510 µm to 1.2050 µm. The mechanical properties of composites are enhanced significantly due to the introduction of Al3Ni and Al2O3 particles, and can be up a YS of 322 MPa and a UTS of 407 MPa in the 15% NiO-Al composite. In addition, when the content of NiO increases from 10% to 12%, the strength of composites enhances without obvious sacrifice of EI. The strengthening and toughening mechanisms also was discussed in detail.

Thermoluminescence properties of nanocrystalline BaSO4 doped with Eu2+ produced by solid state combustion synthesis

Nanocrystalline powder samples of barium sulfate doped with Europium (BaSO4:Eu2+) were prepared, at a dopant concentration of 0.02 mol%, by the combustion solid-state technique in air atmospheres. Thermoluminescence (TL) response and dosimetric studies have been carried out for this phosphor in order to characterize it as a radiation dosimeter. The results showed that the TL glow curve of BaSO4:Eu2+present an intense TL peak at 200 °C accompanied by a small shoulder peak at 270 °C. The TL low detection limit for BaSO4:Eu (0.02 mol%) was found to be 17.8μGy for the gamma radiation emitted by 137Cs. The comparative study with the LiF:Mg, Ti (TLD-100) and calcium fluoride doped with thulium CaF2:Tm dosimeters showed that the TL response of the BaSO4:Eu(0.02 mol%) synthesized by the combustion solid-state technique is highly sensitive: it is 5.8 times higher than the response of the CaF2:Tm pellets and 9.4 times higher than the response of TLD-100. The high sensitivity of BaSO4:Eu and its linear dose response indicate that it can be used as sensor for gamma ionizing radiations.

Facile solid-state combustion synthesis of Al–Ni dual-doped LiMn2O4 cathode materials

A series of aluminum and nickel (Al–Ni) co-doped LiAl0.15NixMn1.85−xO4 composites are prepared through a facile solid-state combustion method. All the as-obtained materials show a spinel structure and analogous spherical morphology with uniform particle distribution. Moreover, the synergistic merits of Al and Ni dual substitutions endow the spinel LiMn2O4 with an elevated Mn average valence state of 3.59 and relatively alleviative Jahn–Teller distortion. Among these samples, the LiAl0.15Ni0.03Mn1.82O4 (LANMO-0.03) cathode exhibits an optimal electrochemical performance with the discharge capacities of 103.3 mAh g−1 and 102 mAh g−1 at 1 C and 5 C in the first cycle, and the capacity retentions are 72.0% and 68.6% after 1000 cycles, respectively. Even at 1 C and high temperature of 55 °C, an excellent capacity retention remained to be 76.6% after 200 cycles. Furthermore, the LANMO-0.03 has good Li+ diffusion capability during charge/discharge, the DLi+ value of the LANMO-0.03 (1.65 × 10–11 cm2∙s−1) is higher than that of the LiAl0.15Mn1.85O4 (LAMO) (8.12 × 10–12 cm2∙s−1), and the charge transfer resistances of the LAMO and LANMO-0.03 samples are almost the same at 150 Ω before cycling but decrease to 130 Ω and 95 Ω after 1000 cycles at 1 C, respectively. These results demonstrate that the Al–Ni co-doped strategy can enhance the structural stability and provide stable Li+ diffusion channel during the long cycles even at elevated temperature. Meanwhile, the facile solid-state combustion approach can also be extended to the preparation of other dual cation-doped electrode materials.

Preparation and Electrochemical Properties of LiMn2O4 by Solid-State Combustion Synthesis Method Using Starch as a Fuel

Preparation and Electrochemical Properties of LiMn2O4 by Solid-State Combustion Synthesis Method Using Starch as a Fuel

Electrochemical performance of spinel LiAlxMn2−xO4 prepared rapidly by glucose-assisted solid-state combustion synthesis

Cathode materials of LiAlxMn2−xO4 (x = 0, 0.02, 0.04, 0.08) with Fd3m space group were synthesized using glucose as the fuel by solid-state combustion synthesis at 500 °C in one hour. The effects of Al-doping on the crystal structures are systematically evaluated by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). The electrochemical performance of the cathode material LiAlxMn2−xO4 was investigated by galvanostatic charge/discharge, cyclic voltammetry (CV) and electrochemical impedance spectra (EIS). Results show that doping Al significantly decreases the lattice parameter, changes the micromorphology and improves the electrochemical performance of LiMn2O4. This novel synthesis method will be benefit for the further improvement of the electrochemical performance of cathode materials in lithium cell.

Electrochemical Properties of LiMn2O4 Prepared by Solid-State Combustion Synthesis Using Oxalic Acid as a Fuel

Electrochemical Properties of LiMn2O4 Prepared by Solid-State Combustion Synthesis Using Oxalic Acid as a Fuel

Effect of Calcination Temperature on the Electrochemical Properties of Spinel LiMn2O4 Prepared by Solid-State Combustion Synthesis

Effect of Calcination Temperature on the Electrochemical Properties of Spinel LiMn2O4 Prepared by Solid-State Combustion Synthesis

Study on the electrochemical performance of high-cycle LiMg0.08Mn1.92O4 cathode material prepared by a solid-state combustion synthesis

LiMg0.08Mn1.92O4 cathode materials were prepared by a solid-state combustion synthesis at different calcination temperatures. The crystal structure was characterized by X-ray diffraction (XRD) analysis and the morphology was observed by scanning electron microscopy (SEM). All the calcined materials were identified as the spinel structure of LiMn2O4. The materials synthesized at 500°C, 600°C and 700°C were single phase, while Mn3O4 impurity phases can be detected in the other materials synthesized at 800°C and 900°C. The average particle size increased with the increase of calcination temperature. The effect of two-stage calcination temperature on the electrochemical properties of the LiMg0.08Mn1.92O4 materials was studied by galvanostatic charge/discharge tests, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements. Results showed that the structural stability of the materials was improved due to Mg-doping. The LiMg0.08Mn1.92O4 materials calcined at 600°C and 700°C demonstrated excellent electrochemical performance with an initial discharge specific capacity of 101.3mAhg−1 and 107.6mAhg−1, and their capacity retention was 98.1% and 94.3% after 40 cycles at 0.2C, respectively.

The Effect of Calcination Time on the Electrochemical Performance of Doped LiMg0.02Mn1.98O4 cathode Material Prepared by Solid-State Combustion Synthesis

The Effect of Calcination Time on the Electrochemical Performance of Doped LiMg0.02Mn1.98O4 cathode Material Prepared by Solid-State Combustion Synthesis

Effect of β-Cyclodextrin on Electrochemical Properties of LiMn<sub>2</sub>O<sub>4</sub> Synthesized by Solid-State Combustion Synthesis

Spinel LiMn2O4 cathode material was rapidly prepared by solid-state combustion synthesis which used lithium carbonate and manganese carbonate as raw materials and β-cyclodextrin as a fuel. The effects of amount of β-cyclodextrin and calcination temperature on their structure and electrochemical properties were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), galvanostatic charge-discharge test and cyclic voltammetry (CV). The optimal synthesis conditions were found to be 5 wt% β-cyclodextrin. Under these conditions, high-purity spinel LiMn2O4 was obtained, and its discharge specific capacity was 110.5 mAh/g in the first cycle and still retained at 99.9 mAh/g after 40 cycles.

Preparation and electrochemical properties of spinel LiMn2O4 prepared by solid-state combustion synthesis

Spinel LiMn2O4 cathode material was rapidly prepared by solid-state combustion synthesis based on a two-stage calcination progress which used lithium carbonate and manganese carbonate as raw materials and citric acid as a fuel. The structure and physicochemical properties of the obtained LiMn2O4 powders were investigated by thermogravimetric analysis (TG) and differential thermal analysis (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), galvanostatic charge–discharge test, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results show that the successful formation of single-phase LiMn2O4 product is highly dependent on its second-stage calcination temperature. Compared with other conditions, the as-prepared LiMn2O4 powders which experienced the second-stage, and calcined at 700 °C is the most uniform, and the charge transfer resistance (Rct) is the lowest, accompanying the best electrochemical activity and highest discharge capacity. Its initial discharge specific capacity is 119.1 mA h/g.

Solid-state combustion synthesis of spinel LiMn2O4 using glucose as a fuel

Spinel LiMn2O4 cathode material was rapidly synthesized in 1 h by solid-state combustion synthesis using metal carbonates as metal ion sources and glucose as a fuel. The effect of different amounts of glucose on the structure and electrochemical performance of as-prepared LiMn2O4 was investigated by X-ray diffraction (XRD), scanning electron micrographs (SEM), galvanostatic charge–discharge test, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). LiMn2O4 spinel was identified as the main crystalline phase with the presence of minor Mn3O4. The amount of glucose greatly affected the formation of Mn3O4. The optimal content of glucose was found to be 10 wt%. Under this condition, the Mn3O4 peaks almost disappeared, and high-purity spinel LiMn2O4 was obtained. Its initial discharge specific capacity of was 125.9 mAh/g, and discharge specific capacity retained at 105.2 mAh/g after 40 cycles. The detail influence of glucose on the electrochemical activity, reversibility and cycling performance of LiMn2O4 was discussed.

Effect of Citric Acid on Electrochemical Properties of Spinel LiMn<sub>2</sub>O<sub>4</sub> Prepared by Solid-State Combustion Synthesis

LiMn2O4 cathode materials were successfully prepared by solid-state combustion synthesis with the lithium carbonate and the manganese carbonate as raw materials and the citric acid as fuel. The effect of citric acid on composition, microstructure and electrochemical properties of LiMn2O4 cathode materials was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV) and galvanostatic charge-discharge test. The results indicated that a pure phase of LiMn2O4 was prepared at the product with 5 wt% citric acid. However, an impure phase of Mn3O4 was found at other products. The crystal size distribution was more uniform at the higher content of citric acid. The products with 5 wt% and 10 wt% citric acid, the cubic structure morphologies of which were more prominent, and the capacities of which were higher than that of bare LiMn2O4 product. Their initial discharge specific capacities were 119.6 mAh•g-1 and 114.0 mAh•g-1, and their capacity retention ratios after 40 cycles were 85.0% and 87.7%, respectively.

Use of Si 3N 4 as a reactant in preparation of TiN–Ti 5Si 3 composites by solid-state SHS reactions

An experimental study on in situ formation of TiN–Ti 5Si 3 composites with a wide range of compositions by self-propagating high-temperature synthesis (SHS) was conducted in two reaction systems. One adopted silicon nitride (Si 3N 4) as the solid source of nitrogen in a solid-state combustion system. The other employed both solid and gaseous reagents and performed the reactions of the Ti–Si powder compact under nitrogen pressures. Self-sustained reactions featuring a distinct combustion front were observed in both systems. TiN–Ti 5Si 3 composites containing Ti 5Si 3 from 20 to 80 mol% were effectively produced by solid-state combustion synthesis of Ti–Si 3N 4 and Ti–Si 3N 4–Si powder compacts. This result verifies the contribution of Si 3N 4 to the formation of TiN and Ti 5Si 3. However, the solid/gas reaction of Ti–Si compacts with gaseous nitrogen was proved to be an inappropriate route in terms of product composition. For the production of a TiN-rich composite such as 80 mol% TiN, it was found that the nitrogen uptake by the Ti–Si sample compact was inadequate, thus resulting in formation of a great amount of Ti 2N in the final product. On the contrary, when preparing the TiN–Ti 5Si 3 composite with a low TiN content like 20 mol% or even 50 mol%, Ti–Si powder compacts in gaseous nitrogen were subjected to excessive Ti nitridation and yielded a Si-rich silicide phase TiSi 2 in addition to TiN and Ti 5Si 3.

Combustion synthesis and characterization of spherical PZT powder

A simple and effective method for the synthesis of PZT powder is reported. Fine spherical powders of PZT [Zr]/[Ti]=52/48 in mol ratio were prepared by solid-state combustion synthesis method based on the reaction of Pb 3O 4, ZrO 2, and TiO 2, activated by KClO 3+1.5C mixture. The powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and LPSA methods. The PZT powder consists of nearly homogenous and spherical grains with an average diameter of 1 μm. An approximate explanation of spherical shape formation is proposed.

La3+and Ce3+Doping of Hard-Magnetic Ferrites

Rare-earth-doped ferrites with the general formula M1 – xR x · nFe2O3 (M = Ba, Sr, Pb; R = La, Ce; x = 0–0.1; n = 4–6) are prepared by solid-state combustion synthesis. The effects of the doping procedure (before or after combustion synthesis), dopant content, and heat-treatment conditions on the magnetic and mechanical properties of the ferrites are examined. The results indicate that doped materials can be used to fabricate permanent magnets with enhanced density, remanence, and energy product. In addition, rare-earth doping improves the strength of the ferrite materials, eliminating their main drawback—inherent brittleness.