A Novel Low‐Firing and Low Loss Microwave Dielectric Ceramic Li2Mg2W2O9 with Corundum Structure

Guo, Huanhuan; Fang, Liang; Jiang, Xuewen; Li, Jie; Lu, Fengqi; Li, Chunchun

doi:10.1111/jace.13829

Cited by 21 publications

(4 citation statements)

References 28 publications

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“…Promising microwave properties have been shown by some materials based on a Li 2 O-WO 3 system, although a majority of these exhibited the dielectric permittivity exceeding 8 and/or a sintering temperature exceeding 800-900 ℃ . Good microwave dielectric properties were found by Guo et al [19] for the Li 2 Mg 2 W 2 O 9 ceramics with a corundum structure sintered at 920 ℃: ε r ≈ 11.5, Q×f ≈ 31,900 GHz (at 10.76 GHz), and τ f ≈ −66.0 ppm/℃. Chen et al [25] reported that the single phase Li 2 W 2 O 7 with an anorthic structure exhibited a very low sintering temperature of 640 ℃ which was well fitted to the ULTCC technology: relative permittivity of 12.2, a quality factor value of 17,700 GHz (at 9.8 GHz), and a temperature coefficient of the resonant frequency of -232 ppm/℃, as well as not reacting with aluminum electrodes.…”

Section: Introductionmentioning

confidence: 73%

“…The list of the crystalline materials characterized by very low sintering temperatures accompanied by good intrinsic dielectric properties (including low dielectric loss) is really short. Besides the quite intensively studied molybdates [3][4][5][6][7][8][9][10][11][12][13][14], some borates [15][16][17][18], and tungstates [19][20][21] are also promising candidates.…”

Section: Introductionmentioning

confidence: 99%

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Ultra-low temperature cofired ceramics based on Li₂WO₄as perspective substrate materials for terahertz frequencies

Szwagierczak¹,

Synkiewicz-Musialska²,

Kulawik³

et al. 2023

Journal of Advanced Ceramics

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With the development of low dielectric permittivity materials having an ultra-low sintering temperature, testing their dielectric properties at terahertz frequencies suitable for 6G communication systems and implementation of the fabricated materials in ultra-low temperature cofired ceramics (ULTCC) were the main goals of the research. Lithium tungstate Li 2 WO 4 was synthesized by a solid-state reaction and used for the preparation of green tapes and test structures with cofired internal conductive layers, which are destined for substrates of microwave and submillimeter wave circuits. Sintering behavior, thermal effects, and mass changes of the green tapes during heating were studied using a hot-stage microscope, differential thermal analysis, and thermogravimetry. A single-phase composition was revealed for being undoped and doped with AlF 3 -CaB 4 O 7 ceramics. The impact of frequency, temperature, the addition of AlF 3 -CaB 4 O 7 and CuBi 2 O 4 dopants, and sintering temperature was the subject of in-depth characterization of dielectric properties in a terahertz region. A glass-free composition, ultra-low sintering temperature of 590-630 ℃, low roughness of the green tapes, dense microstructure, compatibility with Ag conductors, low and stable dielectric permittivity of 5.0-5.8 in a broad range of 0.2-2 THz, and low dielectric loss of 0.008-0.01 at 1 THz are the main advantages of the developed ULTCC substrates.

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Section: Introductionmentioning

confidence: 73%

Section: Introductionmentioning

confidence: 99%

Ultra-low temperature cofired ceramics based on Li₂WO₄as perspective substrate materials for terahertz frequencies

Szwagierczak¹,

Synkiewicz-Musialska²,

Kulawik³

et al. 2023

Journal of Advanced Ceramics

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“…Compared to α-Al 2 O 3 , however, LNWO is a compositionally mixed oxide. There are many examples of binary or ternary oxides displaying a corundum-like structure (Co 4 Nb 2 O 9 , Ni 3 TeO 6 , Mn 2 ScTaO 6 , Li 2 Mg 2 W 2 O 9 , Li 2 GeTeO 6 , etc.). In fact, the crystal structure of LNWO matches with that of another compound, MgNi 3 Nb 2 O 9 , which displays (Mg, Ni)-honeycomb layers caught between Mg–Ni–Nb–O layers made of octahedra chains in a pattern similar to what can be seen in LNWO (Figure ).…”

Section: Discussionmentioning

confidence: 99%

“…Materials with similar lattice structures can frequently be found in the literature, the most prominent being the aforementioned corundum, also known as α-Al 2 O 3 . 67 In fact, it is very easy to transform the lattice of α-Al 2 O 3 (R3̅ c) into the orthorhombic, 71 Li 2 GeTeO 6 , 72 etc.). In fact, the crystal structure of LNWO matches with that of another compound, MgNi 3 Nb 2 O 9 , 73 which displays (Mg, Ni)-honeycomb layers caught between Mg−Ni−Nb−O layers made of octahedra chains in a pattern similar to what can be seen in LNWO (Figure 2).…”

Section: Discussionmentioning

confidence: 99%

Electrochromic Corundum-like Compound Based on the Reversible (De)insertion of Lithium: Li₂Ni₂W₂O₉

Redor,

Godeffroy,

Rousse

et al. 2023

J. Am. Chem. Soc.

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The search for efficient anodic electrochromic materials is essential to the development of electrochromic devices, such as smart windows. Magnetron-sputtered lithium-nickeltungsten mixed oxides are good candidates to tackle this issue; however, they display a complicated microstructure, making it difficult to pinpoint the origin of their electro-optical properties. Herein, by exploring the Li 2 O−NiO−WO 3 phase diagram, we obtained a new phase, Li 2 Ni 2 W 2 O 9 , that crystallizes in the orthorhombic Pbcn space group. This material can reversibly uptake/release 0.75 Li + (31 mA h•g −1 ) when cycled between 2.5 and 5.0 V versus Li + /Li. Moreover, through operando optical microscopy, we show that this new phase is electrochromic, and crucial information can be accessed about the diffusion-limited insertion of lithium at the single-particle scale. This study sets the ground for future syntheses of electrochemically active materials crystallizing in the ramsayite structure and details how the electrochromic properties of battery materials can be used to shed some light on their electrochemical mechanisms.

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List of Low‐Loss Ceramic Dielectric Materials and Their Properties

2017

Microwave Materials and Applications 2V Set

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AbbreviationsST = sintering temperature ( • C) r = relative permittivity , f = measurement frequency (GHz) f = coefficient of temperature variation of resonant frequency (ppm/ • C) No. = serial number Qf = quality factor frequency product (GHz)The table lists the key property data of microwave dielectric materials available from published materials. These data are the relative permittivity ( r ), the product of the Q-factor and the frequency (Qf ), the frequency of measurement (f), and the temperature coefficient of the resonant frequency ( f ). In tabulating these data, we make no judgment on the measurement method and the reliability of the result. It is known that the ceramic properties such as porosity, grain size, raw materials used, impurities, measurement methods, and equipment used for measurements affect the dielectric properties and readers should be aware that exact comparison of data on materials of identical composition and manufactured in different laboratories using different processing conditions and measured by different methods would be expected to lead to small variations in properties. The data of dielectric measurements carried out using impedance methods at low (MHz) frequency is excluded as the errors in these methods mean that a loss tangent less than 10 −3 is unreliable. The data are arranged in the order of increasing relative permittivity. The quality factor of the microwave dielectric ceramics decrease significantly with increasing relative permittivity, as shown in Figure A.1. The inset in the figure shows the variation of quality factor frequency product with Microwave Materials and Applications, First Edition. Edited by Mailadil T. Sebastian, Rick Ubic and Heli Jantunen.

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A Novel Low‐Firing and Low Loss Microwave Dielectric Ceramic Li₂Mg₂W₂O₉ with Corundum Structure

Cited by 21 publications

References 28 publications

Ultra-low temperature cofired ceramics based on Li₂WO₄as perspective substrate materials for terahertz frequencies

Ultra-low temperature cofired ceramics based on Li₂WO₄as perspective substrate materials for terahertz frequencies

Electrochromic Corundum-like Compound Based on the Reversible (De)insertion of Lithium: Li₂Ni₂W₂O₉

List of Low‐Loss Ceramic Dielectric Materials and Their Properties

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A Novel Low‐Firing and Low Loss Microwave Dielectric Ceramic Li2Mg2W2O9 with Corundum Structure

Cited by 21 publications

References 28 publications

Ultra-low temperature cofired ceramics based on Li2WO4as perspective substrate materials for terahertz frequencies

Ultra-low temperature cofired ceramics based on Li2WO4as perspective substrate materials for terahertz frequencies

Electrochromic Corundum-like Compound Based on the Reversible (De)insertion of Lithium: Li2Ni2W2O9

List of Low‐Loss Ceramic Dielectric Materials and Their Properties

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A Novel Low‐Firing and Low Loss Microwave Dielectric Ceramic Li₂Mg₂W₂O₉ with Corundum Structure

Ultra-low temperature cofired ceramics based on Li₂WO₄as perspective substrate materials for terahertz frequencies

Ultra-low temperature cofired ceramics based on Li₂WO₄as perspective substrate materials for terahertz frequencies

Electrochromic Corundum-like Compound Based on the Reversible (De)insertion of Lithium: Li₂Ni₂W₂O₉