Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 40
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Angew Chem Int Ed Engl ; 63(30): e202403189, 2024 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-38701048

RESUMO

Understanding how reaction heterogeneity impacts cathode materials during Li-ion battery (LIB) electrochemical cycling is pivotal for unraveling their electrochemical performance. Yet, experimentally verifying these reactions has proven to be a challenge. To address this, we employed scanning µ-XRD computed tomography to scrutinize Ni-rich layered LiNi0.6Co0.2Mn0.2O2 (NCM622) and Li-rich layered Li[Li0.2Ni0.2Mn0.6]O2 (LLNMO). By harnessing machine learning (ML) techniques, we scrutinized an extensive dataset of µ-XRD patterns, about 100,000 patterns per slice, to unveil the spatial distribution of crystalline structure and microstrain. Our experimental findings unequivocally reveal the distinct behavior of these materials. NCM622 exhibits structural degradation and lattice strain intricately linked to the size of secondary particles. Smaller particles and the surface of larger particles in contact with the carbon/binder matrix experience intensified structural fatigue after long-term cycling. Conversely, both the surface and bulk of LLNMO particles endure severe strain-induced structural degradation during high-voltage cycling, resulting in significant voltage decay and capacity fade. This work holds the potential to fine-tune the microstructure of advanced layered materials and manipulate composite electrode construction in order to enhance the performance of LIBs and beyond.

2.
Small ; 18(30): e2202410, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35726004

RESUMO

The structure-activity relationship is a cornerstone topic in catalysis, which lays the foundation for the design and functionalization of catalytic materials. Of particular interest is the catalysis of the hydrogen evolution reaction (HER) by palladium (Pd), which is envisioned to play a major role in realizing a hydrogen-based economy. Interestingly, experimentalists observed excess heat generation in such systems, which became known as the debated "cold fusion" phenomenon. Despite the considerable attention on this report, more fundamental knowledge, such as the impact of the formation of bulk Pd hydrides on the nature of active sites and the HER activity, remains largely unexplored. In this work, classical electrochemical experiments performed on model Pd(hkl) surfaces, "noise" electrochemical scanning tunneling microscopy (n-EC-STM), and density functional theory are combined to elucidate the nature of active sites for the HER. Results reveal an activity trend following Pd(111) > Pd(110) > Pd(100) and that the formation of subsurface hydride layers causes morphological changes and strain, which affect the HER activity and the nature of active sites. These findings provide significant insights into the role of subsurface hydride formation on the structure-activity relations toward the design of efficient Pd-based nanocatalysts for the HER.


Assuntos
Paládio , Prótons , Catálise , Hidrogênio/química , Paládio/química
3.
Nat Commun ; 13(1): 2261, 2022 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-35477711

RESUMO

Accurate capacity estimation is crucial for the reliable and safe operation of lithium-ion batteries. In particular, exploiting the relaxation voltage curve features could enable battery capacity estimation without additional cycling information. Here, we report the study of three datasets comprising 130 commercial lithium-ion cells cycled under various conditions to evaluate the capacity estimation approach. One dataset is collected for model building from batteries with LiNi0.86Co0.11Al0.03O2-based positive electrodes. The other two datasets, used for validation, are obtained from batteries with LiNi0.83Co0.11Mn0.07O2-based positive electrodes and batteries with the blend of Li(NiCoMn)O2 - Li(NiCoAl)O2 positive electrodes. Base models that use machine learning methods are employed to estimate the battery capacity using features derived from the relaxation voltage profiles. The best model achieves a root-mean-square error of 1.1% for the dataset used for the model building. A transfer learning model is then developed by adding a featured linear transformation to the base model. This extended model achieves a root-mean-square error of less than 1.7% on the datasets used for the model validation, indicating the successful applicability of the capacity estimation approach utilizing cell voltage relaxation.

4.
Nat Chem ; 13(11): 1070-1080, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34531571

RESUMO

Anionic redox is a double-edged sword for Li-ion cathodes because it offers a transformational increase in energy density that is also negated by several detrimental drawbacks to its practical implementation. Among them, voltage hysteresis is the most troublesome because its origin is still unclear and under debate. Herein, we tackle this issue by designing a prototypical Li-rich cation-disordered rock-salt compound Li1.17Ti0.33Fe0.5O2 that shows anionic redox activity and exceptionally large voltage hysteresis while exhibiting a partially reversible Fe migration between octahedral and tetrahedral sites. Through combined in situ and ex situ spectroscopic techniques, we demonstrate the existence of a non-equilibrium (adiabatic) redox pathway enlisting Fe3+/Fe4+ and O redox as opposed to the equilibrium (non-adiabatic) redox pathway involving sole O redox. We further show that the charge transfer from O(2p) lone pair states to Fe(3d) states involving sluggish structural distortion is responsible for voltage hysteresis. This study provides a general understanding of various voltage hysteresis signatures in the large family of Li-rich rock-salt compounds.

5.
Inorg Chem ; 60(8): 5497-5506, 2021 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-33829762

RESUMO

Lithium iron phosphate, LiFePO4, a widely used cathode material in commercial Li-ion batteries, unveils a complex defect structure, which is still being deciphered. Using a combined computational and experimental approach comprising density functional theory (DFT)+U and molecular dynamics calculations and X-ray and neutron diffraction, we provide a comprehensive characterization of various OH point defects in LiFePO4, including their formation, dynamics, and localization in the interstitial space and at Li, Fe, and P sites. It is demonstrated that one, two, and four (five) OH groups can effectively stabilize Li, Fe, and P vacancies, respectively. The presence of D (H) at both Li and P sites for hydrothermally synthesized deuterium-enriched LiFePO4 is confirmed by joint X-ray and neutron powder diffraction structure refinement at 5 K that also reveals a strong deficiency of P of 6%. The P occupancy decrease is explained by the formation of hydrogarnet-like P/4H and P/5H defects, which have the lowest formation energies among all considered OH defects. Molecular dynamics simulation shows a rich structural diversity of these defects, with OH groups pointing both inside and outside vacant P tetrahedra creating numerous energetically close conformers, which hinders their explicit localization with diffraction-based methods solely. The discovered conformers include structural water molecules, which are only by 0.04 eV/atom H higher in energy than separate OH defects.

6.
ACS Appl Mater Interfaces ; 13(5): 6309-6321, 2021 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-33527829

RESUMO

We studied the structural evolution and cycling behavior of TiNb2O7 (TNO) as a cathode in a nonaqueous hybrid dual-salt Mg-Li battery. A very high fraction of pseudocapacitive contribution to the overall specific capacity makes the material suitable for ultrafast operation in a hybrid battery, composed of a Mg-metal anode, and a dual-salt APC-LiCl electrolyte with Li and Mg cations. Theoretical calculations show that Li intercalation is predominant over Mg intercalation into the TNO in a dual-salt electrolyte with Mg2+ and Li+, while experimentally up to 20% Mg cointercalation was observed after battery discharge. In hybrid Mg-Li batteries, TNO shows capacities which are about 40 mA h g-1 lower than in single-ion Li batteries at current densities of up to 1.2 A g-1. This is likely due to a partial Mg cointercalation or/and location of Li cations on alternative crystallographic sites in the TNO structure in comparison to the Li-intercalation process in Li batteries. Generally, hybrid Mg-Li cells show a markedly superior applicability for a very prolonged operation (above 1000 cycles) with 100% Coulombic efficiency and a capacity retention higher than 95% in comparison to conventional Li batteries with TNO after being cycled either under a low (7.75 mA g-1) or high (1.55 A g-1) current density. The better long-term behavior of the hybrid Mg-Li batteries with TNO is especially pronounced at 60 °C. The reasons for this are an appropriate cathode electrolyte interface containing MgCl2 species and a superior performance of the Mg anode in APC-LiCl electrolytes with a dendrite-free, fast Mg deposition/stripping. This stable interface stands in contrast to the anode electrolyte interface in Li batteries with a Li anode in conventional carbonate-containing electrolytes, which is prone to dendrite formation, thus leading to a battery shortcut.

7.
J Phys Condens Matter ; 33(10): 105901, 2021 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-33237884

RESUMO

Diffraction and imaging using x-rays and neutrons are widely utilized in different fields of engineering, biology, chemistry and/or materials science. The additional information gained from the diffraction signal by x-ray diffraction and computed tomography (XRD-CT) can give this method a distinct advantage in materials science applications compared to classical tomography. Its active development over the last decade revealed structural details in a non-destructive way with unprecedented sensitivity. In the current contribution an attempt to adopt the well-established XRD-CT technique for neutron diffraction computed tomography (ND-CT) is reported. A specially designed 'phantom', an object displaying adaptable contrast sufficient for both XRD-CT and ND-CT, was used for method validation. The feasibility of ND-CT is demonstrated, and it is also shown that the ND-CT technique is capable to provide a non-destructive view into the interior of the 'phantom' delivering structural information consistent with a reference XRD-CT experiment.

8.
Nat Commun ; 11(1): 1252, 2020 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-32144249

RESUMO

High-energy-density lithium-rich materials are of significant interest for advanced lithium-ion batteries, provided that several roadblocks, such as voltage fade and poor energy efficiency are removed. However, this remains challenging as their functioning mechanisms during first cycle are not fully understood. Here we enlarge the cycling potential window for Li1.2Ni0.13Mn0.54Co0.13O2 electrode, identifying novel structural evolution mechanism involving a structurally-densified single-phase A' formed under harsh oxidizing conditions throughout the crystallites and not only at the surface, in contrast to previous beliefs. We also recover a majority of first-cycle capacity loss by applying a constant-voltage step on discharge. Using highly reducing conditions we obtain additional capacity via a new low-potential P" phase, which is involved into triggering oxygen redox on charge. Altogether, these results provide deeper insights into the structural-composition evolution of Li1.2Ni0.13Mn0.54Co0.13O2 and will help to find measures to cure voltage fade and improve energy efficiency in this class of material.

9.
Inorg Chem ; 59(2): 1532-1546, 2020 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-31913612

RESUMO

MnSnTeO6, a new chiral antiferromagnet, was prepared both by topotactic transformation of the metastable rosiaite-type polymorph and by direct synthesis from coprecipitated hydroxides. Its structure and its static and dynamic magnetic properties were studied comprehensively both experimentally (through X-ray and neutron powder diffraction, magnetization, specific heat, dielectric permittivity, and ESR techniques) and theoretically (by means of ab initio density functional theory (DFT) calculations within the spin-polarized generalized gradient approximation). MnSnTeO6 is isostructural with MnSb2O6 (space group P321) and does not show any structural transition between 3 and 300 K. The magnetic susceptibility and specific heat exhibit an antiferromagnetic ordering at TN ≈ 9.8 K, which is confirmed by low-temperature neutron data. At the same time, the thermodynamic parameters demonstrate an additional anomaly on the temperature dependences of magnetic susceptibility χ(T), specific heat Cp(T) and dielectric permittivity ε(T) at T* ≈ 4.9 K, which is characterized by significant temperature hysteresis. Clear enhancement of the dielectric permittivity at T* is most likely to reflect the coupling of dielectric and magnetic subsystems leading to development of electric polarization. It was established that the ground state of MnSnTeO6 is stabilized by seven exchange parameters, and neutron diffraction revealed incommensurate magnetic structure with propagation vector k = (0, 0, 0.183) analogous to that of MnSb2O6. Ab initio DFT calculations demonstrate that the strongest exchange coupling occurs between planes along diagonals. All exchange parameters are antiferromagnetic and reveal moderate frustration.

10.
Nat Commun ; 10(1): 5365, 2019 11 26.
Artigo em Inglês | MEDLINE | ID: mdl-31772159

RESUMO

One major challenge in the field of lithium-ion batteries is to understand the degradation mechanism of high-energy lithium- and manganese-rich layered cathode materials. Although they can deliver 30 % excess capacity compared with today's commercially- used cathodes, the so-called voltage decay has been restricting their practical application. In order to unravel the nature of this phenomenon, we have investigated systematically the structural and compositional dependence of manganese-rich lithium insertion compounds on the lithium content provided during synthesis. Structural, electronic and electrochemical characterizations of LixNi0.2Mn0.6Oy with a wide range of lithium contents (0.00 ≤ x ≤ 1.52, 1.07 ≤ y < 2.4) and an analysis of the complexity in the synthesis pathways of monoclinic-layered Li[Li0.2Ni0.2Mn0.6]O2 oxide provide insight into the underlying processes that cause voltage fading in these cathode materials, i.e. transformation of the lithium-rich layered phase to a lithium-poor spinel phase via an intermediate lithium-containing rock-salt phase with release of lithium/oxygen.

11.
J Am Chem Soc ; 141(36): 14200-14209, 2019 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-31403777

RESUMO

Solid electrolytes with superionic conductivity are required as a main component for all-solid-state batteries. Here we present a novel solid electrolyte with three-dimensional conducting pathways based on "lithium-rich" phosphidosilicates with ionic conductivity of σ > 10-3 S cm-1 at room temperature and activation energy of 30-32 kJ mol-1 expanding the recently introduced family of lithium phosphidotetrelates. Aiming toward higher lithium ion conductivities, systematic investigations of lithium phosphidosilicates gave access to the so far lithium-richest compound within this class of materials. The crystalline material (space group Fm3m), which shows reversible thermal phase transitions, can be readily obtained by ball mill synthesis from the elements followed by moderate thermal treatment of the mixture. Lithium diffusion pathways via both tetrahedral and octahedral voids are analyzed by temperature-dependent powder neutron diffraction measurements in combination with maximum entropy method and DFT calculations. Moreover, the lithium ion mobility structurally indicated by a disordered Li/Si occupancy in the tetrahedral voids plus partially filled octahedral voids is studied by temperature-dependent impedance and 7Li NMR spectroscopy.

12.
J Am Chem Soc ; 141(27): 10595-10598, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31251610

RESUMO

Electrides are ionic crystals in which the electrons prefer to occupy free space, serving as anions. Because the electrons prefer to be in the pockets, channels, or layers to the atomic orbitals around the nuclei, it has been challenging to find electrides with partially filled d-shell transition metals, since an unoccupied d-shell provides an energetically favorable location for the electrons to occupy. We recently predicted the existence of electrides with partially filled d-shells using high-throughput computational screening. Here, we provide experimental support using X-ray absorption spectroscopy and X-ray and neutron diffraction to show that Sr3CrN3 is indeed an electride despite its partial d-shell configuration. Our findings indicate that Sr3CrN3 is the first known electride with a partially filled d-shell transition metal, in agreement with theory, which significantly broadens the criteria for the search for new electride materials.

13.
ChemistryOpen ; 8(1): 74-83, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30693170

RESUMO

The reaction of Fe(NO3)3⋅9 H2O with KOH under hydroflux conditions at about 200 °C produces red crystals of K2-x Fe4O7-x (OH) x in a quantitative yield. In the crystal structure, edge-sharing [FeO6] octahedra form ∞ 2 [ Fe2O6] honeycomb nets. Pillars consisting of pairs of vertex-sharing [FeO4] tetrahedra link the honeycomb layers and form columnar halls in which the potassium ions are located. The trigonal (P 3 ‾ 1m) and the hexagonal (P63/mcm) polytypes of K2-x Fe4O7-x (OH) x show oriented intergrowth. The sub-stoichiometric potassium content (x≈0.3) is compensated by hydroxide ions. K2-x Fe4O7-x (OH) x is an antiferromagnet above 2 K and its magnetic structure was determined by neutron powder diffraction. Under ambient conditions, K2-x Fe4O7-x (OH) x hydrolyzes and K2CO3 ⋅ H2O forms gradually on the surface of the K2-x Fe4O7-x (OH) x crystals. Upon annealing at air at about 500 °C, the potassium atoms in the columnar halls start to order into a superstructure. The thermal decomposition of K2-x Fe4O7-x (OH) x proceeds via a topotactic transformation into K1+x' Fe11O17, adopting the rhombohedral ß'' or the hexagonal ß-aluminate-type structure, before γ-Fe2O3 is formed above 950 °C, which then converts into thermodynamically stable α-Fe2O3.

14.
J Am Chem Soc ; 140(47): 16330-16339, 2018 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-30380843

RESUMO

Solid-state batteries with inorganic solid electrolytes are currently being discussed as a more reliable and safer future alternative to the current lithium-ion battery technology. To compete with state-of-the-art lithium-ion batteries, solid electrolytes with higher ionic conductivities are needed, especially if thick electrode configurations are to be used. In the search for optimized ionic conductors, the lithium argyrodites have attracted a lot of interest. Here, we systematically explore the influence of aliovalent substitution in Li6+ xP1- xGe xS5I using a combination of X-ray and neutron diffraction, as well as impedance spectroscopy and nuclear magnetic resonance. With increasing Ge content, an anion site disorder is induced and the activation barrier for ionic motion drops significantly, leading to the fastest lithium argyrodite so far with 5.4 ± 0.8 mS cm-1 in a cold-pressed state and 18.4 ± 2.7 mS cm-1 upon sintering. These high ionic conductivities allow for successful implementation within a thick-electrode solid-state battery that shows negligible capacity fade over 150 cycles. The observed changes in the activation barrier and changing site disorder provide an additional approach toward designing better performing solid electrolytes.

15.
Chem Commun (Camb) ; 54(88): 12523-12526, 2018 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-30345452

RESUMO

The new phase Co2ScSbO6 and Ni2-xCoxScSbO6 solid solutions adopt the polar Ni3TeO6-type structure and order magnetically below 60 K. A series of long-period lock-in [0 0 1/3n] spin structures with n = 5, 6, 8 and 10 is discovered, coexisting with a ferrimagnetic [0 0 0] phase at high Co-contents. The presence of electrical polarisation and spontaneous magnetisations offers possibilities for multiferroic properties.

16.
ACS Appl Mater Interfaces ; 10(42): 36108-36119, 2018 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-30251827

RESUMO

Two new structural forms of Na xCo0.5Ti0.5O2, the layered O3- and P3-forms, were synthesized and comprehensively characterized. Both materials show electrochemical activity as electrodes in Na-ion batteries. During cell charging (desodiation of the Na xCo0.5Ti0.5O2 cathode), we observed a structural phase transformation of O3-Na0.95Co0.5Ti0.5O2 into P3-Na xCo0.5Ti0.5O2, whereas no changes other than conventional unit cell volume shrinkage were detected for P3-Na0.65Co0.5Ti0.5O2. During Na insertion (cell discharging), the reconversion of the P3-form into O3-Na xCo0.5Ti0.5O2 was impeded for both materials and occurs well below 1 V versus Na+/Na only. The reconversion is hindered by the charge and spin transfers of Co (LS-Co3+ → HS-Co2+) and by a significant unit cell volume expansion at the P3 → O3 transformation, as revealed from the magnetization, crystallographic, and spectroscopic studies. As the kinetics of such transformations depend on numerous parameters such as time, temperature, and particle size, a large cell overpotential ensues. An extended cutoff voltage at 0.2 V versus Na+/Na during discharging allows to complete the P3 → O3 transformation and increases the specific discharging capacity to 200 mA h g-1. Moreover, a quasi-symmetrical full cell, based on the O3- and P3-forms, was designed, eliminating safety concerns associated with sodium anodes and delivering a discharge capacity of 130 mA h g-1.

17.
J Appl Crystallogr ; 51(Pt 3): 591-595, 2018 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-29896055

RESUMO

The need for rapid data collection and studies of small sample volumes in the range of cubic millimetres are the main driving forces for the concept of a new high-throughput monochromatic diffraction instrument at the Heinz Maier-Leibnitz Zentrum (MLZ), Germany. A large region of reciprocal space will be accessed by a detector with sufficient dynamic range and microsecond time resolution, while allowing for a variety of complementary sample environments. The medium-resolution neutron powder diffraction option for 'energy research with neutrons' (ErwiN) at the high-flux FRM II neutron source at the MLZ is foreseen to meet future demand. ErwiN will address studies of energy-related systems and materials with respect to their structure and uniformity by means of bulk and spatially resolved neutron powder diffraction. A set of experimental options will be implemented, enabling time-resolved studies, rapid parametric measurements as a function of external parameters and studies of small samples using an adapted radial collimator. The proposed powder diffraction option ErwiN will bridge the gap in functionality between the high-resolution powder diffractometer SPODI and the time-of-flight diffractometers POWTEX and SAPHiR at the MLZ.

18.
Inorg Chem ; 57(10): 5820-5829, 2018 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-29737843

RESUMO

The crystal structure of CaFe4Al8 was studied by X-ray single crystal and powder diffraction as well as high-resolution neutron powder diffraction. CaFe4Al8 crystallizes with a tetragonal CeMn4Al8-type structure, an ordered variant of the ThMn12-type (Pearson symbol tI26, space group I4/ mmm, a = 8.777(1), c = 5.077(1) Å). Similarly to the well-known A15-type superconductors, the structure of CaFe4Al8 contains one-dimensional chains of d-metal atoms, which are parallel to the crystallographic fourfold axis. CaFe4Al8 is paramagnetic at room temperature and exhibits long-range antiferromagnetic ordering at about 180 K, combined with a short-range ordered spin arrangement. The magnetic structure, determined by powder neutron diffraction at 4 K, shows that the magnetic moments on the Fe atoms form mirror-inverted chains along the c-direction and are slightly canted from the axis.

19.
Nat Mater ; 17(5): 427-431, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29632408

RESUMO

Piezoelectric actuators transform electrical energy into mechanical energy, and because of their compactness, quick response time and accurate displacement, they are sought after in many applications. Polycrystalline piezoelectric ceramics are technologically more appealing than single crystals due to their simpler and less expensive processing, but have yet to display electrostrain values that exceed 1%. Here we report a material design strategy wherein the efficient switching of ferroelectric-ferroelastic domains by an electric field is exploited to achieve a high electrostrain value of 1.3% in a pseudo-ternary ferroelectric alloy system, BiFeO3-PbTiO3-LaFeO3. Detailed structural investigations reveal that this electrostrain is associated with a combination of several factors: a large spontaneous lattice strain of the piezoelectric phase, domain miniaturization, a low-symmetry ferroelectric phase and a very large reverse switching of the non-180° domains. This insight for the design of a new class of polycrystalline piezoceramics with high electrostrains may be useful to develop alternatives to costly single-crystal actuators.

20.
ACS Appl Mater Interfaces ; 10(13): 10935-10944, 2018 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-29516733

RESUMO

Li1+ xAl xGe2- x(PO4)3 (LAGP) is a solid lithium-ion conductor belonging to the NASICON family, representing the solid solution of LiGe2(PO4)3 and AlPO4. The typical syntheses of LAGP either involve high-temperature melt-quenching, which is complicated and expensive, or a sol-gel process requiring costly organic germanium precursors. In this work, we report a simple method based on aqueous solutions without the need of ethoxide precursors. Using synchrotron and neutron diffraction, the crystal structure, the occupancies for Al and Ge, and the distribution of lithium were determined. Substitution of germanium by aluminum allows for an increased Li+ incorporation in the material and the actual Li+ content in the sample increases with the nominal Li+ content and a solubility limit is observed for higher aluminum content. By means of impedance spectroscopy, an increase in the ionic conductivity with increasing lithium content is observed. Whereas the lithium ionic conductivity improves, due to the increasing carrier density, the bulk activation energy increases. This correlation suggests that changes in the transport mechanism and correlated motion may be at play in the Li1+ xAl xGe2- x(PO4)3 solid solution.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...