Direct microwave sintering of pure alumina in a single mode cavity: Grain size and phase transformation effects

Croquesel, Jérémy; Bouvard, D.; Chaix, Jean‐Marc; Carry, C.; Saunier, Sébastien; Marinel, Sylvain

doi:10.1016/j.actamat.2016.06.027

Cited by 53 publications

(19 citation statements)

References 36 publications

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“…Schemes fort he solid-based synthetic approaches for NaSICON-type Li-ion conductors:a)solid-statereaction;b)melt quenching;c )spark plasma sintering (SPS [66] ); d) field-assisted sintering technique(FAST [63] ); and e) microwave (MW)-assisted sintering [68] .c)-e) Reproduced with permission from Refs. [63,66,68]. www.chemsuschem.org also enables the large-scale synthesis of LATP solid electrolytes.…”

Section: Sol-gel Methodsmentioning

confidence: 99%

“…[66,67] FAST applies av oltage exclusively to the sample during sintering to increase the resistivity of the material and then achieveasimilare ffect to that of solid-state sintering. [68] Although complicated instru- ments are required, these fast sintering techniques have shown ultrafastt imescales, while providing excellent control over compositiona nd phases.I na ddition, rapid heating rates, localized heatinga tt he grain boundaries, or the electric-fieldenhancing diffusion mechanisms of theset echniques contribute to the enhanced conductive properties of the obtained solid electrolytes. [68] Although complicated instru- ments are required, these fast sintering techniques have shown ultrafastt imescales, while providing excellent control over compositiona nd phases.I na ddition, rapid heating rates, localized heatinga tt he grain boundaries, or the electric-fieldenhancing diffusion mechanisms of theset echniques contribute to the enhanced conductive properties of the obtained solid electrolytes.…”

Section: Fast Sintering Techniquesmentioning

confidence: 99%

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Synthesis and Properties of NaSICON‐type LATP and LAGP Solid Electrolytes

2019

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Inorganic solid electrolytes, in comparison with their liquid counterparts, have more potential in varioust ypes of batteries due to their dual roles of ion transportation and separation. For all-solid-state batteries, solide lectrolytes bring several advantages, [1][2][3][4][5][6] such as enhanced safety,i ncreased energy density,s olid device integration, and packaging;t hese expand the operation temperature range and potentially improve cycling stabilitya nd lifetime. Moreover,i norganic solid electrolytes are also beneficial for lithium-ion batteries and lithium-air batteries, in which they functiona se ither surface modification layers or lithium-ion conductors. [7,8] In principle, ideal solid electrolytes are expected to have several features: [9][10][11][12][13][14] 1) fast ion dynamics and negligible electronic conductivity (minimum ionic conductivity of 10 À4 Scm À1 at room temperature for practical consideration);2 )a wide electrochemical potential window for battery cycling;3 )ane xceptional mechanical strength to suppress lithium dendrite growth;4 )excellent thermal stability during the cycling processes;and 5) asimple and low cost synthetic process for large-scale applications.Generally,i norganic lithium superionic conductors are divided into three categories:o xides, sulfides, and phosphates. Suc-cessfule xamples in oxidesi nclude garnet oxides, [15,16] perovskite-type oxides, [17,18] and antiperovskite oxides. [19][20][21] Sulfide solid electrolytes include Li 2 SÀP 2 S 5 , [22,23] Li 3 PS 4 , [24][25][26] Li 7 P 3 S 11 , [27,28] Li 7 PS 6 ,a nd Li 6 PS 5 X( X = Cl, Br). [29][30][31] Popular phosphate solid electrolytes include sodium superionic conductor (NaSICON)structured lithium-ion conductors, [32][33][34][35][36] such as LiTi 2 (PO 4 ) 3 (LTP), Li 1 + x Al x Ti 2Àx (PO 4 ) 3 (LATP), and Li 1 + x Al x Ge 2Àx (PO 4 ) 3 (LAGP). Many exciting discoveries of these materials have been summarized in important review papers. [2,6,[37][38][39][40] NaSICON-type solid electrolytes, such as LATP and LAGP, have marked advantages compared with sulfides and oxides: they display chemicals tabilityi na ir and/or water,a re low cost and low toxicity,a nd have great electrochemical stability with the added benefito fe asy preparation. [2,36,38] They also exhibit attractive ionic conductivities of 10 À4 -10 À3 Scm À1 at room temperature. Such features have recently caused renewed interest in these NaSICON-structured materials and much effort has been devoted to the investigation of this type of solid electrolyte, especiallyL ATPa nd LAGP.T his manuscript reviewsr ecent progress in LATP and LAGP solid electrolytes, with as pecific focus on synthetic approaches and their effects on the crystal structures, conductive properties, and applications. Herein, general synthetic methods for LATP and LAGP solid electrolytes are first introduced, followed by ac omparison of the crystal structures, phase purities, and ionic conductivities that result from different approaches. Later,t he applications of LATP and LAGP in ful...

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Section: Sol-gel Methodsmentioning

confidence: 99%

Section: Fast Sintering Techniquesmentioning

confidence: 99%

Synthesis and Properties of NaSICON‐type LATP and LAGP Solid Electrolytes

2019

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“…The as-synthesized pellet was then heated in air in a 2.45 GHz monomode micro-wave cavity (Sairem) at different powers and dwelling times. Samples were placed at the maximum of the electrical field, according to the protocol 5 previously described by Croquesel et al [19,20]. The temperature was measured with a pyrometer located at around 20 cm of the surface of the pellet.…”

Section: Introductionmentioning

confidence: 99%

Microwave-assisted reactive sintering and lithium ion conductivity of Li1.3Al0.3Ti1.7(PO4)3 solid electrolyte

Hallopeau

Brégiroux

Rousse

et al. 2018

Journal of Power Sources

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Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 (LATP) materials are made of a threedimensional framework of TiO 6 octahedra and PO 4 tetrahedra, which provides several positions for Li + ions. The resulting high ionic conductivity is promising to yield electrolytes for all-solid-state Li-ion batteries. In order to elaborate dense ceramics, conventional sintering methods often use high temperature ( 1000°C) with long dwelling times (several hours) to achieve high relative density ( 90%).In this work, an innovative synthesis and processing approach is proposed. A fast and easy processing technique called microwave-assisted reactive sintering is used to both synthesize and sinter LATP ceramics with suitable properties in one single step. Pure and crystalline LATP ceramics can be achieved in only 10 min at 890 °C starting from amorphous, compacted LATP's precursors powders. Despite a relative density of 88%, the ionic conductivity measured at ambient temperature (3.15 x 10 -4 S.cm -1 ) is among the best reported so far. The study of the activation energy for Li + conduction confirms the high quality of the ceramic (purity and crystallinity) achieved by using this new approach, thus emphasizing its interest for making ion-conducting ceramics in a simple and fast way.

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“…The pellets achieve 99.2% of the theoretical density at 1430 ℃ for a soaking duration of 20 min. A non-linear interaction of microwave with space charges induced by the electric field in a non-perfect crystalline solid generates a force similar to ponderomotive force in plasma science, which may be the reason behind the fast densification of the sample [33].…”

Section: Resultsmentioning

confidence: 99%

Influence of La3+ ion in the yttria matrix in improving the microhardness of infrared transparent nano LaxY2-xO3 sintered via hybrid heating

et al. 2017

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Abstract:In the present work, hybrid sintering technique which couples the resistive heating and microwave heating is employed to sinter infrared transparent La 0.15 Y 1.85 O 3 to 99.2% of the theoretical density for the first time to the best of our knowledge. The presence of La 3+ in the yttria matrix improves the hardness properties to a greater extent without affecting the transmittance properties, but there is a deterioration in the thermal properties of the sample. So we have limited our studies to La 0.15 Y 1.85 O 3 which shows better optical, thermal, and hardness properties. The pellets fabricated from the ultra-fine nano powder with average particle size of ~12 nm synthesized by combustion technique and sintered at 1430 ℃ with an average grain size of 0.22 µm show ~80.1% transmittance in the UV-visible region and 81% in mid infrared region. For a comparative study of the optical, mechanical, and thermal properties, two other variants of sintering strategies namely conventional sintering and microwave sintering are also employed. A comprehensive analysis on the hardness reveals that the hardness of the pellets sintered via hybrid heating is 9.73 GPa and is superior to the pellets sintered using the other two techniques. The thermal conductivity of the sample is also analyzed in detail. The results clearly indicate that the La 0.15 Y 1.85 O 3 ultra-fine nano powder synthesised by the single-step combustion method and sintered via microwave hybrid heating shows better transmittance properties without compromising the mechanical properties, and can be used very effectively for the fabrication of infrared transparent windows and domes.

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Direct microwave sintering of pure alumina in a single mode cavity: Grain size and phase transformation effects

Cited by 53 publications

References 36 publications

Synthesis and Properties of NaSICON‐type LATP and LAGP Solid Electrolytes

Synthesis and Properties of NaSICON‐type LATP and LAGP Solid Electrolytes

Microwave-assisted reactive sintering and lithium ion conductivity of Li1.3Al0.3Ti1.7(PO4)3 solid electrolyte

Influence of La3+ ion in the yttria matrix in improving the microhardness of infrared transparent nano LaxY2-xO3 sintered via hybrid heating

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