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1.
Artigo em Inglês | MEDLINE | ID: mdl-34428373

RESUMO

Li7La3Zr2O12(LLZO)-based ceramics as promising solid-state electrolytes (SSEs) have received much attention for use in high-energy lithium (Li) metal batteries. However, the Li growth through the solid garnet electrolyte under a low current density hinders its practical application. In this work, the Cu doped Li3Zn was designed to guide uniform Li deposition by magnetron cosputtering and an in situ alloying reaction on Li6.5La3Zr1.5Ta0.5O12 (LLZTO) pellets. After introducing the composite layer, a small interfacial area specific resistance (∼30 Ω·cm2) can be obtained. Improved lithium plating/stripping performance, including a long-life span of 450 h (under a current density of 0.8 mA cm-2 without short circuit) and a high critical current density (CCD) of 2.8 mA cm-2 is performed by the composite interlayer with a Zn:Cu ratio of 10:1. And the Li/Cu-Li3Zn SSEs/LFP full cell exhibits good electrochemical performance. Accordingly, the Li deposited behavior in the Li plating/stripping process at the intermediate layer is discussed in detail. This work provides a new sight for the alloy interface designed on the solid-state garnet SSEs for high performance lithium metal batteries under high current density.

2.
Sensors (Basel) ; 21(16)2021 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-34450980

RESUMO

Copper (II) ions have been shown to greatly improve the chemical stability and peroxidase-like activity of gold nanoclusters (AuNCs). Since the affinity between Cu2+ and pyrophosphate (PPi) is higher than that between Cu2+ and AuNCs, the catalytic activity of AuNCs-Cu2+ decreases with the introduction of PPi. Based on this principle, a new colorimetric detection method of PPi with high sensitivity and selectivity was developed by using AuNCs-Cu2+ as a probe. Under optimized conditions, the detection limit of PPi was 0.49 nM with a linear range of 0.51 to 30,000 nM. The sensitivity of the method was three orders of magnitude higher than that of a fluorescence method using AuNCs-Cu2+ as the probe. Finally, the AuNCs-Cu2+ system was successfully applied to directly determine the concentration of PPi in human urine samples.


Assuntos
Ouro , Nanopartículas Metálicas , Colorimetria , Cobre , Difosfatos , Corantes Fluorescentes , Humanos , Limite de Detecção , Peroxidase , Peroxidases , Espectrometria de Fluorescência
3.
ACS Appl Mater Interfaces ; 13(12): 14385-14393, 2021 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-33736429

RESUMO

Herein, the second-order Jahn-Teller effect was applied to the design of the bismuth ferrite-based ceramics. A large distortion of an electron structure arranged along the z axis and an asymmetric distribution of charge density were calculated in 0.80(0.725BiFeO3-0.275BaTiO3)-0.20PT (0.20 PT) based on the density functional theory, indicating good ferro/piezoelectric properties. The top experimental polarization of 36.89 µC/cm2, optimal d33 value of 258 pC/N measured at room temperature, and ultrahigh d33 value of 303 pC/N measured at 370 °C were obtained at 0.20 PT, thereby further confirming the calculations. Furthermore, a high Curie point of 488 °C, as well as outstanding temperature stability ranging from room temperature to 430 °C of the 0.20 PT ceramic was observed. The domain of the 0.20 PT exhibited greater order and smaller size, resulting in easy switching when applying voltage. The distorted electron structure, plumb grains, ordered and easily switchable domains, and coexistences of tetragonal (T) and rhombohedral (R) phases contributed to the large piezoelectric constant of the 0.2 PT ceramic. BFBT-xPT ceramics are potentially promising for high-temperature piezoelectric field applications.

4.
Dalton Trans ; 49(17): 5573-5580, 2020 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-32270800

RESUMO

Here, (1 -x)BiFe0.98(Zn0.5Hf0.5)0.02O3-xBaTiO3 + 1 mol% MnO2 (x = 0.225, 0.250, 0.265, 0.275, 0.285, and 0.300) (BFZH-xBT) ceramics were synthesized using a traditional ceramic sintering technique. A morphotropic phase boundary (MPB) consisting of rhombohedral (R) and tetragonal (T) phases was formed in the BFZH-xBT ceramics when x = 0.285. The suitable content of BT was conducive to enlarge the particle size, improve ferroelectric and piezoelectric properties, and reduce the leakage current density. For the optimal component at x = 0.285, we observed the largest grain size, a lowest leakage current density value of ∼1.93 × 10-5 A cm-2, minimum content of oxygen vacancies, high temperature of 478 °C and the highest piezoelectric coefficient (d33) of 130 pC N-1.

5.
Inorg Chem ; 57(3): 1251-1258, 2018 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-29341598

RESUMO

In this paper, a joint strategy was proposed to investigate the microscopic origin of the second-harmonic-generation (SHG) response in nonpolar ABCO3F compounds. The SHG coefficients of ABCO3F were evaluated using finite-field and sum-over-states methods. The tendency of the obtained SHG tensors is in good agreement with the powder SHG response. The atomic contribution was investigated using variation of the atomic charges and bandwidth of occupied atomic states. The results show that oxygen states play a key role in determining the SHG response, and the neighboring divalent cations exert a indirect influence via covalent interaction. The bidentate bonding pattern is beneficial to obtaining a largely enhanced SHG response.

6.
Dalton Trans ; 47(3): 750-757, 2018 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-29243745

RESUMO

Two new rare-earth borates, MBaYB6O12 (M = Rb, Cs), which are the first reported compounds in M2O-BaO-RE2O3-B2O3 (M = Rb, Cs; RE = rare-earth) quaternary systems, have been discovered through a high-temperature solution method and their structures were determined by single-crystal X-ray diffraction. These two compounds are isostructural with the centrosymmetric space group R3[combining macron] (no. 148) and the fundamental building blocks are the B3O6 groups which are nearly parallel to each other. The spectral measurement shows that the cutoff edges of the two compounds are all down to the deep-ultraviolet (deep-UV) region (below 200 nm). And the experimental birefringence of RbBaYB6O12 and RbBaYB6O12 is about 0.12 at 589 nm. Moreover, first-principles theoretical studies were carried out to gain a better understanding of the structure-property relationships. The calculation results demonstrate that both the compounds have a large birefringence of 0.100 at 589 nm, which corresponds to the experimental value. Both experimental and theoretical studies suggest that MBaYB6O12 (M = Rb, Cs) are potential birefringent materials for UV and deep-UV applications.

7.
J Am Chem Soc ; 137(29): 9417-22, 2015 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-26147880

RESUMO

Pb(II) has long been associated with lone pair activity and is often substituted in alkali earth metal borates to create new nonlinear optical (NLO) materials with enhanced second harmonic generation (SHG) capabilities. However, large enhancement in isomorphic Pb-free analogues is rare. Here we report a new NLO material Pb2Ba3(BO3)3Cl with a phase-matching SHG response approximately 3.2× that of KDP and 6× higher than its isomorphic compound Ba5(BO3)3Cl. We show that the enhanced SHG response originates from a unique edge-sharing connection between lead-oxygen polyhedra and boron-oxygen groups, making the dielectric susceptibility more easily affected by the external electric field of an incident photon. This understanding provides a route to identify systems that would benefit from SHG-active cation substitution in isomorphic structures that exhibit weak or null SHG responses.

8.
Chemistry ; 19(23): 7338-41, 2013 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-23630069

RESUMO

Borate not graphene: The [B6O12]∞(6-) single borate layer is a graphene-like layer (see figure). The weak Na(+)-Br(Cl)(-) ionic connection between the layers leads to the layer cleavage, and difficulty of the block crystal growth.

9.
Inorg Chem ; 51(20): 10870-5, 2012 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-23005578

RESUMO

A new noncentrosymmetric borophosphate, Na(3)Cd(3)B(PO(4))(4), has been successfully synthesized by conventional solid state reaction for the first time. It crystallizes in the orthorhombic space group Pmc2(1) with unit cell parameters of a = 13.6854(3) Å, b = 5.3346(11) Å, c = 18.2169(4) Å, and Z = 4. Na(3)Cd(3)B(PO(4))(4) features zero-dimensional [B(PO(4))(4)](9-) anion units with Cd(2+) and Na(+)/Cd(2+) cations located around them, in which the BO(4) tetrahedron is surrounded by four PO(4) tetrahedra by sharing the vertexes of O atoms. Second harmonic generation (SHG) measurements show that Na(3)Cd(3)B(PO(4))(4) exhibits a SHG response 1.1 times larger than that of KH(2)PO(4) (KDP) and is phase matchable.

10.
Chemistry ; 18(38): 12046-51, 2012 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-22887000

RESUMO

A new series of anhydrous mixed alkali-metal borophosphates--Li(2)Cs(2)B(2)P(4)O(15) (1), LiK(2)BP(2)O(8) (2), Li(3)K(2)BP(4)O(14) (3), and Li(3)Rb(2)BP(4)O(14) (4)--have been successfully synthesized by using the conventional solid-state reaction method. Compound 1 contains a novel fundamental building unit (FBU), [B(4)P(8)O(30)], with B/P = 1:2. Compound 2 contains an FBU of [B(2)P(4)O(16)] with B/P = 1:2. Compounds 3 and 4 are isotypic, and they have a [B(P(2)O(7))(2)] unit as their FBU. In all four compounds, their FBUs are connected through corner sharing to generate layered anionic partial structures, and then further linked with metallic polyhedra to form three-dimensional (3D) frameworks. Most interestingly, three of the four compounds contain direct P-O-P connections in their structures, which is extremely rare among borophosphates. Thermal analyses, IR spectroscopy, and UV/Vis/near-IR diffuse reflectance spectroscopy have also been performed on the four title compounds.

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