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Highlights: [•] A new beryllium borate SrBeB2O5 was synthesized. [•] A layered structure (BeB2O5)∞ was formed by BO3 triangles and B/BeO4 tetrahedrons. [•] SrBeB2O5 has a very wide transparency range of wavelengths from 200nm to 1800nm. [•] A-site ions impact greatly on the structures of beryllium borates. [ABSTRACT FROM AUTHOR]

Highlights: [•] New borate–malate crystals NaB(DL-C4H4O5)2 and CsB(DL-C4H4O5)2⋅H2O have been grown. [•] They display diverse framework geometries attributable to the size of the cations. [•] NaB(DL-C4H4O5)2 crystallizes in the noncentrosymmetric monoclinic space group P2. [•] Both crystals have absorption edges about 220nm in the UV region. [•] NaB(DL-C4H4O5)2 exhibits a NLO efficiency of 2times that of KDP (KH2PO4) standard. [ABSTRACT FROM AUTHOR]

Highlights: [•] Semiorganic NLO material NaB(L-C4H4O5)2 has been grown with sizes up to 8×5×2mm3. [•] It crystallizes in the noncentrosymmetric Monoclinic space group P2. [•] Thermal analysis demonstrated NaB(L-C4H4O5)2 are thermally stable up to 280. [•] NaB(L-C4H4O5)2 has an absorption edge about 220nm in the UV region. [•] It exhibits a NLO efficiency of about two times that of KDP (KH2PO4) standard. [ABSTRACT FROM AUTHOR]

Abstract: A novel fluorine beryllium borate crystal Sr0.23Ca0.77Na2Be2B2O6F2 has been grown by high temperature solution method from its self-flux system for the first time. Crystal structure of this compound was determined by single crystal X-ray diffraction. It crystallizes in the trigonal space group (No. 148) with lattice parameters a=4.6608(6) Å, c= 27.516(5) Å, Z=3, V= 517.65(13) Å3. The crystal displays a sandwich-like layered configuration along c axis with the infinite (Be6B6O12F3)∞ non-bonding double layer formed by two (Be3B3O6F3)∞ single layers in the a-b plane. The single layer was composed of BO3 triangle and BeO3F tetrahedron, both of which are the most favorable anionic groups in deep ultraviolet (UV) region. The structural relationship between the title compound and related fluorine beryllium borate was discussed. Optical transmittance spectrum reveals this compound has a very wide transmission range (190nm – 8μm). The IR spectrum and thermal behavior of Sr0.23Ca0.77Na2Be2B2O6F2 were also reported. [Copyright &y& Elsevier]

Abstract: A novel beryllium borate CsBe4(BO3)3 has been grown in crystals by high-temperature flux method using spontaneous nucleation technique for the first time. The crystal structure of this compound was determined by single crystal X-ray diffraction analysis. It crystallizes in the orthorhombic space group Pnma with lattice parameters a = 8.3914(5) Å, b = 13.3674(7) Å, c = 6.4391(3) Å, Z = 4, V = 722.28(7) Å3. The crystal takes the same structure type as Rb analog based on the units of BO3 triangles and BeO4 tetrahedrons, displaying a three-dimensional tunnel structure with Cs atoms filling in the cages. The IR spectrum confirms the presence of BO3 groups and the UV–vis–IR diffuse reflectance spectrum exhibits this compound has a short UV cut-off edge below 200 nm. Band structures and density of states were calculated. [Copyright &y& Elsevier]

A single crystal of the new noncentrosymmetric material Cs2Ca[B4O5(OH)4]2·8H2O has been grown by a slow evaporation method with sizes up to 10×10×5mm3 using an aqueous acetone solution as a solvent. The crystal structure of this compound was determined by single crystal X-ray diffraction. It crystallizes in the Orthorhombic space group P212121 with lattice parameters a=11.5158(7)Å, b=12.8558(7)Å, c=16.7976(10)Å and Z=4. The optical transmittance spectrum was measured on the Cs2Ca[B4O5(OH)4]2·8H2O crystal, which exhibits an absorption edge at about 190nm in the UV region. The powder second-harmonic generation (SHG) measurement indicates that Cs2Ca[B4O5(OH)4]2·8H2O is phase-matchable and the signal is about half that of a KDP (KH2PO4) standard. Theoretical calculation shows it has moderate birefringence, and identifies the contribution of cations to the optical properties. [ABSTRACT FROM AUTHOR]

Due to the shortage of lithium resources, current lithium-ion batteries are difficult to meet the growing demand for energy storage in the long run. Rechargeable aqueous aluminum ion (Al3+) electrochemistry has the advantages of abundant resources, high safety, environmental friendliness, and high energy/power density. It is, therefore an ideal choice for alternative energy storage devices. However, Al3+-based technology is still in the preliminary stage, and there are various challenges. In reality, its kinetics and reversibility have long been disturbed by the strong electrostatic field of Al3+ and the parasitic side reactions of aqueous electrolytes. This paper first summarizes the history of aqueous aluminum ion batteries/capacitors (AAIBs/AAICs) and analyzes the challenges faced by cathode, anode, and electrolyte. Then, the state-of-the-art research progress, design strategies, and limitations of the cathode, anode, electrolyte, and Al3+-based energy storage devices are comprehensively introduced, and their structure, performance, and reaction mechanisms are discussed. Finally, the future design of AAIBs/AAICs with long life, high reversibility, and high energy/power density has been prospected, and promising research directions are pointed out. [ABSTRACT FROM AUTHOR]

Potassium-ion batteries (KIBs) have attracted more and more attention due to the abundant potassium resources and hence low cost of raw materials. Nevertheless, the performances of KIBs are still unsatisfactory for practical applications, mainly due to the lack of suitable cathode materials. In this work, we report for the first time a novel polyanionic compound K 1+δ VOPO 4 F as a potassium ion storage host. Thanks to its flexible while stable layered [VOPO 4 F] ∞ framework, as a KIB cathode material, it can provide a reversible capacity of about 101 mAh g−1 at a rate of 0.2 C with a 87% capacity retention after 250 cycles. The corresponding energy density of 363 Wh kg−1 is among the highest for K-ion storage. The working mechanism of the V4+/V5+ redox reaction is determined by in-situ X-ray diffraction (XRD) and ex situ X-ray photoelectron spectra (XPS) analyses. Notably, it delivers a stable average capacity of 75 mAh g−1 for 700 cycles at 1 C with a capacity retention rate of 76%. This work presents that K 1+δ VOPO 4 F is a promising K+ storage cathode material with merits of high energy density and long cyclability. [Display omitted] • We first report a novel polyanionic compound K 1+δ VOPO 4 F as a K-ion storage host. The structure is reported for the first time. • With flexible and stable layered [VOPO 4 F] ∞ framework, good structural stability and reversibility. • As a KIB cathode, it displays a high average discharge voltage of 3.6 V and a high reversible capacity of 101 mAh g−1. • Excellent cycle stability, it delivers a stable 700 cycles with a capacity retention rate of 76%. • High energy density of 363 Wh kg−1 can be obtained. [ABSTRACT FROM AUTHOR]