Octahedral Distortion Research Articles

Emerging mixed electronic-ionic conductivity in double perovskite (La2/3Sr1/3)2(Sn1/3Fe1/3Cu1/3)2O6-δ: Phase transitions, structural, optical and dielectric study

We report on the eco-friendly synthesis of a double perovskite compound (La2/3Sr1/3)2(Sn1/3Cu1/3Fe1/3)2O6-δ, attractive for sustainable applications due to its unique structural and conductive properties. The incorporation of Cu2+ (3d9) ions into the B sites of the perovskite structure enhanced octahedral distortion via the Jahn-Teller effect. X-ray crystallography and Rietveld structural analysis revealed a significant deviation in the octahedra of (Cu/Fe)O6 and (Sn/Fe)O6 from the ideal perovskite structure, resulting in a decreased overlap between the atomic orbitals. The material displays a high dielectric constant, evidenced by impedance measurements across varying temperatures and frequencies. The analysis highlighted a considerable influence of the grain intrinsic properties and the grain boundary dynamics on both the conduction mechanism and dielectric relaxation. Notably, the introduction of dopants significantly reduces the bandgap energy to 2.7eV, compared to the 4.3eV of SrSnO3. The bandgap reduction factor measured here is lower than that of other reported double-doped SrSnO3 compounds. At 493K, a transition in DSC measurements suggests a structural change of the conductivity from a purely electronic to an electronic-ionic conductivity. The smaller bandgap and enhanced conductivity, coupled with phase transitions lead to a mixed conductivity making this material particularly effective for the use in energy storage technologies such as supercapacitors and batteries with the aim of improving their capacity and efficiency. Additionally, due to its temperature sensitivity, it also has the potential to be used as a valuable component in sensor applications.

IMPACT OF Ca DOPING ON THE STRUCTURAL CHARACTERISTICS OF La1-XCaXFe0.5Mn0.5O3

A series of perovskite compounds La1-xCaxFe0.5Mn0.5O3 (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 and 0.9) were synthesized using the conventional ceramic method. The influence of the Ca-doping on the crystal structure of these compounds was studied using was investigated through X-ray diffraction (XRD) and Raman scattering spectroscopy. XRD analysis revealed that all the samples crystallize in an orthorhombic structure with the Pbnm space group. The variation in lattice parameters, bond lengths and bond angles created by the difference in valence state and ion size due to the Ca-doping leads to the distortion and tilt of octahedra in the samples.

Engineering the Effective Mass in 2D Perovskites via Octahedral Distortion

Engineering the Effective Mass in 2D Perovskites via Octahedral Distortion

Role of ZnO dopant in enhancing piezoelectric characteristics in KNN‐based piezoelectric ceramics

AbstractConsidering that lead‐based piezoelectric ceramics are not conducive to sustainable development, the research and preparation of environmentally friendly lead‐free piezoelectric ceramics has become a new trend. Among them, potassium‐sodium niobate based (KNN‐based) piezoelectric ceramics are considered as the most potential candidates because of their good piezoelectric properties. However, the strong sensitivity to temperature has hindered the further application of KNN‐based ceramics. In this work, the ZnO dopant was introduced in 0.96K0.48Na0.52Nb0.96Sb0.04O3–0.04Bi0.5Na0.5HfO3 ceramics to improve their piezoelectric characteristics. On the one hand, Zn2+ could occupy B‐site and thus enhance the lattice distortion of BO6 octahedra, resulting the enhanced piezoelectric properties including kp = 46%, d33 = 344 pC/N and TC = 282°C in the optimal component with x = 0.01. On the other hand, the defect dipole formed by the acceptor dopant Zn2+ pinned the motion of domain wall, and thus improved the temperature stability over a wide temperature range of 20°C to 180°C, where the descent in unipolar strain decreased from 35% (x = 0) to 23% (x = 0.01). This work provides a point of view about how ZnO dopants make an influence on the KNN‐based ceramics.

Modification Orbital Electronic States in Nickel-Based Hydroxides Via Cobalt/Iron Co-Doping for High-Efficiency Methanol Electrooxidation.

The nickel hydroxide-based (Ni(OH)2) methanol-to-formate electrooxidation reaction (MOR) performance is greatly related to the orbital electronic states. Hence, optimizing the orbital electronic states to achieve enhanced MOR activities are highly desired. Here, cobalt (Co) and iron (Fe) doping are used to modify the orbital electronic states. Although both dopants can broaden the orbital; however, Co doping leads to an elevation in the energy level of highest occupied crystal orbital (HOCO), whereas Fe doping results in its reduction. Such a discrepancy in the regulation of orbital electronic states stems from the disparate partial electron transfer mechanisms amongst these transition metal ions, which possess distinct energy level and occupancy of d orbitals. Motivated by this finding, the NiCoFe hydroxide is prepared and exhibited an excellent MOR performance. The results showed that the Co dopants effectively suppress the partial electron transfer from Ni to Fe, combined with the orbital broadening induced by NiO6 octahedra distortion, endowing NiCoFe hydroxide with high HOCO and broad orbital. It is believed that the work gives an in-depth understanding on orbital electronic states regulation in Ni(OH)2, which is beneficial for designing Ni(OH)2-based catalysts with high MOR performance.

Durable Photo-Pyroelectric Detection in a Diamine-Constructed Lead-Free Hybrid Perovskite Ferroelectric.

As a subcategory of pyroelectric materials, hybrid perovskite ferroelectrics possess substantial pyroelectric properties and exceptional light absorption characteristics, demonstrating significant potential in the photo-pyroelectric (PPE) detection field. Despite the significant advantages of hybrid perovskite ferroelectric materials for PPE detection, both the lead issue and the weak stability from van der Waals interactions in monoamines have hindered their further application. Here, 1D lead-free ferroelectric (BDA)SbBr5 (1, where BDA is 1,4-butanediammonium) is fabricated to achieve PPE detection. Compound 1 exhibits significant symmetry breaking attributed to the order-disorder transition of organic cations and octahedral distortions. Specifically, compound 1 enables broad-spectrum PPE detection from UV to near-infrared (377-980nm) and further realizes switchable pyroelectric current after polarization. More importantly, the stability of the pyroelectric current is preserved without degradation over three months, attributed to the hydrogen bonding interactions of butanediamide. Further theoretical calculations of compound 1 reveal a more negative energy of formation than its monoamine homologs (BA)2SbBr5 (where BA is n-butylammonium), which is evidence of its stability. These findings highlight 1 as a promising candidate for high-stability and environmentally friendly PPE wide-spectrum detection, representing a noteworthy advancement in the ferroelectric field.

Enhanced magnetoelectric response in Sc-doped BiFeO3-BaTiO3 Ceramics

In recent years, the single-phase BiFeO3-BaTiO3 multiferroic ceramics have gained attention for their magnetoelectric response above room temperature, but substantial endeavors to improve the property have yielded modest results. An optimized BiFe(1-x)ScxO3-BaTiO3 composition having magnetoelectric coefficient (αME) ∼ 567 mV/(cm·Oe)) measured at the resonant frequency (∼95 kHz) is reported in this work. The high αME is attributed to the combined effect of improved piezoelectric coefficient and enhanced ferromagnetism. Improved piezoelectricity is attributed to enhanced intrinsic response caused by the octahedral distortions, and enhanced ferromagnetism is induced by the destabilized cycloidal spin structure resulting from the octahedral distortions. Besides, the addition of Sc3+ can exhibit increased resistivity and reduced defect dipole effects, which is conducive to improving electric properties.

Tunable ferromagnetism via in situ strain engineering in single-crystal freestanding SrTiO3-δ membrane

Engineering stoichiometry and lattice field in transition metal oxides (TMOs) is recognized as a promising approach for achieving emergent functional properties and exploring fundamental scientific questions. To overcome the constraints of rigid epitaxial TMOs, this study releases and transfers freestanding SrTiO3-δ (STO3-δ) membranes, derived using a water-dissolution method from STO3-δ/Sr3Al2O6/SrTiO3, onto flexible polyimide. In-plane mechanical strains were then applied to investigate the strain evolution-induced ferromagnetism. Continuous strain modulates interplane and intraplane exchange interactions between neighboring atoms in the ferromagnetic STO3-δ membranes, thereby influencing their ferromagnetic properties. STO3-δ initially undergoes in-plane octahedral distortion when strain is less than 1.5 %, followed by a decrease in the out-plane lattice constant. This structural variation leads to complex strain-dependent behaviors in the saturation magnetic moment (Ms) and coercive field (Hc) of STO3-δ, with Ms and Hc exhibiting a nonlinear, volcano-shaped, and step-wise correlation, respectively. Our research demonstrates that freestanding STO3-δ serves as a platform for studying local defects and their impacts on tunable magnetic properties, greatly enhancing our understanding of t2g electron engineering through modulable inter/intra plane exchange coupling with lattice field.

Substitution of Ce4+ for ionic at both A/B sites greatly improves the microwave responses of (Sr0.9Ca0.1)1/2La1/2Al1/2Ti1/2O3 perovskite ceramics

In this paper, (Sr0.9Ca0.1)1/2La1/2Al1/2Ti1/2O3-x wt.% CeO2 (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5) ceramics were synthesized via solid state reaction. The effects of Ce4+ doping on microstructure and microwave dielectric properties were studied. All samples crystallized as perovskite single-phase. Ce4+ substitution for La3+ occurred at the A site for 0 < x ≤ 0.4, and for Ti4+ at the B site for 0.4 ≤ x ≤ 0.5. Oxygen vacancy concentration was linked to substitution sites, decreasing for x ≤ 0.3 and increasing for x ≥ 0.4, as shown by XPS analysis. The quality factor was influenced by oxygen vacancies, grain size, and packing fraction. Bonding valence and oxygen octahedral distortion affected the temperature coefficient of resonant frequency. At x = 0.4 and sintered at 1570 °C, the ceramics showed excellent properties: εr = 38.83, Q×f = 54058 GHz, τf = 2.137 ppm/°C, making it a promising low-loss dielectric ceramic for microwave communication applications.

Praseodymium induced symmetry switching and electrochemical characteristics of LaCoO3 nanostructures

A comparative study of the crystal structures and electrochemical characteristics of bulk and nanoscale La1-xPrxCoO3 (x = 0, 0.3 and 0.6) perovskites is made using synchrotron x-ray diffraction, cyclic voltammetry, and galvanostatic charge/discharge methods. It is shown that the sol-gel synthesized nano structures and bulk LaCoO3 exhibit different crystal structures, viz., rhombohedral [a = b = 5.4401 Å, c = 13.134 Å (on hexagonal axes), Z = 6, R3‾c] and monoclinic [am = 5.3865 Å, bm = 5.4482 Å, cm = 7.6365 Å, βm = 89.010°, Z = 4, I2/a], respectively. The evidence for CoO6 octahedra distortion in bulk LaCoO3 is also gathered from the three distinct Raman active modes at 518, 646, and 688 cm−1 emerging due to the Jahn-Teller effect, which, in-turn, reduces the crystal symmetry for achieving structure stabilization. This amounts to changes in Co–O bond lengths and Co–O–Co bond angles with promotion of t2g electron to eg level simultaneously for Co3+(3d6) to attain an intermediate spin state (S = 1) or higher. However, Pr-insertion induces phase transition to orthorhombic in both but with space group Pnma in nanostructures and equivalent Pbnm in bulk. The substitution effect on the specific capacitance (C) is opposite in nature, i.e., while ‘C’ decreases from 149 to 12 F/g in nano structures, it increases from 0.4 to 4 F/g in bulk with increase in Pr-content from x=0 to 0.6. A galvanostatic charge-discharge test of pristine nano LaCoO3 performed at a constant scan rate of 50 mVs−1 reveals electrode electrochemical stability by retaining 96 % of specific capacitance ∼82.5 F/g for 2000 cycles at least. The variation in the crystal structure and bond length and/or angle plays a key role in controlling the electrochemical performance of Pr-substituted LaCoO3 perovskites.

Superconducting transition of GdBa2Cu3O7-x/La0.7A0.3MnO3 (A=Sr and Ca) bilayers governed by tunable interlayer structural coupling

Bilayers composed of high-Tc cuprate superconductors (HTS) with manganites have garnered significant attention due to the complex interaction between two layers, leading to competition among various ordering phenomena. When HTS and manganties are interfaced, new functionalities can emerge that are absent in the individual components. Notably, epitaxial strain can alter crystal structures and electronic states, significantly impacting superconductivity in HTS/manganite heterostructures. In this study, we analyze the superconducting and ferromagnetic behaviors of GdBa2Cu3O7-x(GdBCO)/La0.7A0.3MnO3(LAMO, where A=Sr and Ca) bilayers, maintain a constant GdBCO thickness of 500 nm while varying the LAMO thickness from 25 to 100 nm. We focus on the local structural correlations between the two layers. Temperature-dependent EXAFS spectra were systematically measured at the Cu and Mn K-edges to investigate the local atomic structures of both layers across the superconducting transition temperature (Tc). Our spectroscopic measurements reveal distinct conformations of the MnO6 octahedra near Tc, which are absent in single-layer LSMO, indicating structural coupling between the layers. Additionally, our magnetization studies show a strong relationship between the structural coupling, magnetic anisotropy (MA), and the superconducting transition of the GdBCO/LAMO bilayers. The additional distortion of the MnO6 octahedra in the GdBCO/LAMO bilayer, likely stemming from structural coupling, may account for the changes in the superconducting transition associated with magnetic anisotropy. This modification of structural coupling can be controlled by adjusting the LAMO thickness, yet it remains highly dependent on the bond geometry of LAMO. The Mn-O bond in LCMO is stiffer than in LSMO, resulting in a smaller change in structural coupling with varying thickness in LCMO compared to LSMO. The disparity in structural coupling directly impacts the magnetic properties of the LAMO layer and subsequently influences the superconducting property ΔTc. Our findings highlight the significance of structural coupling as a critical factor affecting the superconductivity of GdBCO/LAMO bilayers. Furthermore, this study provide foundational insight for designing various applications, such as magnetic sensors and spintronic devices, by enhancing our understanding of local dynamics at the interface between ferromagnets and superconductors.

From LaCrO3 towards LaCr0.2Mn0.2Fe0.2Al0.2Ga0.2O3 high-entropy ceramic compound: Crystal structure, dielectric and magnetic properties

A group of five perovskite-type ceramic systems was designed by solid-state reaction, increasing the configurational entropy, ΔSconf at the B-site, going from low and medium to finally reaching a high-entropy system. Chemical elements, crystal structure, and microstructure characterization, as well as the dielectric and magnetic properties, are discussed from the single phase LaCrO3 towards a continuous equiatomic multicomponent LaCr0.2Mn0.2Fe0.2Al0.2Ga0.2O3 ceramic compounds. Through a combination of structural analysis and XPS spectroscopy study, it is found that not only the configurational entropy ∆Sconf term, but also the enthalpy of mixing, ΔHmix through of arising of the coexistence of mixed valence state, oxygen vacancies, and local octahedral distortions lead to the stabilization of the single phase in equimolar multicomponent perovskite systems. The arising of Cr3+/Cr6+ and Mn3+/Mn2+ mixed valence state drives the AC electric conductivity through the presence of two kinds of charge carriers, small polarons and oxygen vacancies in LCM, LCMF, LCMFA, and LCMFAG ceramic compounds. The occurrence of these two classes of charge carriers progressively increases the AC electric conductivity at room and high temperatures for each ceramic compound, being higher for the LCMFA entropy compound, making it a potential candidate for solid oxide fuel cell (SOFC) applications. As expected, the increases of compositional random cations display rich magnetic properties arising from competing magnetic interactions driven by the sublattice of Cr, Mn, and Fe magnetic ions. The resulting ΔSconf increase leads to a Griffith-like phase. The results also show that not only the ferromagnetic clusters of the LaMnO3 (AxFz) sublattice but also the weak ferromagnetism associated with the LaCrO3 (GxFz), and LaFeO3 (GxFz) sublattices play a predominant role in the formation of the Griffiths-like phase in the low, medium and high-entropy ceramic systems.

Se‐dopant Modulated Selective Co‐Insertion of H+ and Zn2+ in MnO2 for High‐Capacity and Durable Aqueous Zn‐Ion Batteries

AbstractMnO2 is commonly used as the cathode material for aqueous zinc‐ion batteries (AZIBs). The strong Coulombic interaction between Zn ions and the MnO2 lattice causes significant lattice distortion and, combined with the Jahn–Teller effect, results in Mn2+ dissolution and structural collapse. While proton intercalation can reduce lattice distortion, it changes the electrolyte pH, producing chemically inert byproducts. These issues greatly affect the reversibility of Zn2+ intercalation/extraction, leading to significant capacity degradation of MnO2. Herein, we propose a novel method to enhance the cycling stability of δ‐MnO2 through selenium doping (Se−MnO2). Our work indicates that varying the selenium doping content can regulate the intercalation ratio of H+ in MnO2, thereby suppressing the formation of ZnMn2O4 by‐products. Se doping mitigates the lattice strain of MnO2 during Zn2+ intercalation/deintercalation by reducing Mn−O octahedral distortion, modifying Mn−O bond length upon Zn2+ insertion, and alleviating Mn dissolution caused by the Jahn–Teller effect. The optimized Se−MnO2 (Se concentration of 0.8 at.%) deposited on carbon nanotube demonstrates a notable capacity of 386 mAh g−1 at 0.1 A g−1, with exceptional long‐term cycle stability, retaining 102 mAh g−1 capacity after 5000 cycles at 3.0 A g−1.

Near‐Full‐Spectrum Emission Realized in a Single Lead Halide Perovskite across the Visible‐Light Region

AbstractThe engineering of tunable photoluminescence (PL) in single materials with a full‐spectrum emission represents a highly coveted objective but poses a formidable challenge. In this context, the realization of near‐full‐spectrum PL emission, spanning the visible light range from 424 to 620 nm, in a single‐component two‐dimensional (2D) hybrid lead halide perovskite, (ETA)2PbBr4 (ETA+=(HO)(CH2)2NH3+), is reported, achieved through high‐pressure treatment. A pressure‐induced phase transition occurs upon compression, transforming the crystal structure from an orthorhombic phase under ambient conditions to a monoclinic structure at high pressure. This phase transition driven by the adaptive and dynamic configuration changes of organic amine cations enables an effective and continuous narrowing of the band gap in this halide crystal. The hydrogen bonding interactions between inorganic layers and organic amine cations (N−H⋅⋅⋅Br and O−H⋅⋅⋅Br hydrogen bonds) efficiently modulate the organic amine cations penetration and the octahedral distortion. Consequently, this phenomenon induces a phase transition and results in red‐shifted PL emissions, leading to the near‐full‐spectrum emission. This work opens a possibility for achieving wide PL emissions with coverage across the visible light spectrum by employing high pressure in single halide perovskites.

Sn4+ Alloying and Chiral Incorporation into Tellurium Halides Triggering Tunable Luminescence Emission and Second-Harmonic Generation.

Recently, chiral organic-inorganic hybrid metal halides have attracted considerable interest as promising multifunctional materials, benefiting from their diverse structures and tunable photophysical properties. Herein, by introducing the chiral ligand methylbenzylamine (R-/S-MBA) and alloying Sn4+ cation, a series of tellurium-based halides R-/S-MBA2SnxTe1-xCl6 (x = 0, 0.125, 0.2, 0.365 and 0.54) with second-harmonic generation (SHG) effect and photoluminescence (PL) properties are successfully synthesized. Their optical bandgaps are determined to be 2.48-2.6 eV. Specifically, the introduction of chiral organic cations could break the structural symmetry and cause the tellurium halide to crystallize in the chiral space group. The incorporation of isovalent Sn4+ into the chiral host tellurium halides results in the increase in octahedral distortion, thereby promoting host intrinsic self-trapped emission that originates from the interconfigurational 3P0,1 → 1S0 transitions of Te4+. Consequently, the as-prepared Sn4+ doped halides, R-/S-MBA2SnxTe1-xCl6 (x = 0.365, 0.54), exhibit not only SHG response but also bright orange fluorescence. This study provides an effective strategy for designing chiral multifunctional materials.

High thermoelectric performance of n–type SrTiO3 by Dy and Nb co–doping

The effects of Dy/Nb co–doping on the structural and thermoelectric properties of Sr1−xDyxTi1−yNbyO3−δ (0 ≤ x, y ≤ 0.10) are systematically investigated. Single–doped Sr0.95Dy0.05TiO3−δ and SrTi0.95Nb0.05O3−δ consist of tetragonal (I4/mcm space group) and cubic (Pm3¯m space group) perovskite phases. On the other hand, Dy/Nb co–doped SrTiO3, Sr1−xDyxTi1−yNbyO3−δ, has a tetragonal perovskite phase (I4/mcm space group) since the Dy/Nb co–doping induces a distortion of the TiO6 octahedra and lowers the crystal symmetry. The co–doping effectively increases the electrical conductivity and reduces the thermal conductivity, thus noticeably enhancing the dimensionless figure–of–merit (ZT). The highest ZT value (0.24) is achieved for Sr0.95Dy0.05Ti0.95Nb0.05O3−δ at 600 °C. This ZT value is 41 % and 50 % larger than those of single–doped Sr0.95Dy0.05TiO3−δ (0.17) and SrTi0.95Nb0.05O3−δ (0.16), respectively, at 600 °C.

Rare Earth‐Induced CoO6 Octahedral Distortion in Perovskite: An Efficient Catalytic Platform for RuO2‐Catalyzed Water Oxidation

Rare Earth‐Induced CoO₆ Octahedral Distortion in Perovskite: An Efficient Catalytic Platform for RuO₂‐Catalyzed Water Oxidation

Significantly enhancing high-temperature piezoelectric response and Tdr of BF-BT-based ceramics through multi-component optimization strategy

Phase boundary-domain engineering modulation with diverse group elements and coexistence of multiphase and composite domain structures is a good pathway that can be realized to simultaneously improve the piezoelectric properties of BF-BT ceramics and their thermal stability. Here, we propose a multicomponent optimization strategy. We innovatively introduce the 0.8(Bi0.5Na0.5)TiO3-0.2(Bi0.5K0.5)TiO3 (BNT-20BKT) component to 0.69BF-0.31BT ceramic, to build a morphotropic phase boundary (MPB) for enhancing d33. Meanwhile, Bi(Zn0.5Ti0.5)O3 with high Curie temperature and high tetragonal degree was introduced with the expectation of obtaining higher thermal stability along with high piezoelectric properties. The 0.69BiFeO3-0.31BaTiO3-0.005[0.8(Bi0.5Na0.5)TiO3-0.2(Bi0.5K0.5)TiO3]-xBi(Zn0.5Ti0.5)O3 (referred to as BF31BT-0.005(BNT-20BKT)-xBZT, 0.00 ≤ x ≤ 0.025) ceramics were successfully prepared. For the first time, an ultra-high piezoelectric performance of 749.6 pC/N was achieved at a real-time depolarization temperature (Tdr) of 395.6 °C, reflecting the real-time piezoelectric properties and ultra-high temperature stability of the ceramic at high temperatures. A two-phase coexisting structure of R and PC phases was produced in BF31BT-0.005(BNT-20BKT)-0.025BZT ceramic. TEM results showed the formation of nanodomains and a large number of polar nanoregions (PNRs). By adjusting the appropriate R/PC phase ratio, oxygen octahedral distortion, and optimizing the local domain engineering, an effective strategy is provided for simultaneously achieving ultra-high temperature stability and ultra-high piezoelectric response.

Copper substituted manganese Prussian blue analogue composite nanostructures for efficient aqueous zinc-ion batteries

Aqueous zinc (Zn)-ion batteries (AZIBs) are considered a promising green energy storage alternative due to their large capacity, low cost, and exceptional safety. Prussian blue analogues (PBAs) with a robust three-dimensional structure and extensive ion channels are highly favorable for Zn2+ insertion/extraction, surpassing manganese (Mn) and vanadium oxides. Herein, copper (Cu) substituted Mn PBA (CuMn PBA) composite nanostructures are synthesized via a simple water-based co-precipitation technique using different concentrations of Cu and Mn sources. The partial substitution of Cu and the formation of Mn vacancies prevent Jahn-Teller distortions of MnN6 octahedra, extending the lifespan. The CuMn PBA-2 electrode exhibits a high discharge capacity of 175.14 mA h g−1 at 0.5 A g−1, superior rate capability of 89.08 mA h g−1 at 2.4 A g−1, and robust cycling stability, maintaining 73.15 mA h g−1 over 2000 cycles at 3 A g−1. Furthermore, the distinct structure provides numerous active sites and reduces volume volatility during cycling. The presence of Cu enhances electrode conductivity, thereby promoting a higher rate of Zn-ion diffusion between electrodes. The reversible intercalation and deintercalation of Zn2+ ions in the CuMn PBA-2 cathode are substantiated by ex-situ analysis methods. This work presents a novel approach for producing high-performance and stable PBA cathode materials for AZIBs.

Orthorhombic Polar Phase in Sodium Niobate Nanoribbons.

Ferroelectric materials exhibit switchable spontaneous polarization below Curie's temperature, driven by octahedral distortions and rotations, as well as ionic displacements. The ability to manipulate polarization coupled with persistent remanence, drives diverse applications, including piezoelectric devices. In the last two decades, nanoscale exploration has unveiled unique material properties influenced by morphology, including the capability to manipulate polarization, patterns, and domains. This paper focuses on the characterization of nanometric sodium niobate (SN) synthesized from metallic niobium through alkali hydrothermal treatment, utilizing electron microscopy techniques, including high-resolution differential phase contrast (DPC) in scanning transmission electron microscopy (STEM). The material exhibits a nanoribbon structure forming a tree root-like network. The study identifies crystallographic phase, atomic columns displacement directions, and surface features, such as exposed planes and the absence of particular atomic columns. The high sensitivity of integrated DPC images proves crucial in overcoming observational challenges in other STEM modes. These observations are essential for potential applications in electronic, photocatalytic, and chemical reaction contexts.