Poly(2,5-benzimidazole)/TriSilanolPhenyl POSS Composite Membranes for Intermediate Temperature PEM Fuel Cells

Novel organic-inorganic composites were in-situ synthesized by using TriSilanolPhenyl polyhedral oligomeric silsesquioxane（SO-POSS） as fillers and poly（2,5-benzimidazole）（ABPBI） as polymer matrix. The uniformly dispersed 3% SO-POSS particles in ABPBI matrix increased the thermal stability of the composite membranes. It was found that both the water and H3PO4 uptakes were increased significantly with the addition of SO-POSS due to the formation of hydrogen bonds between the POSS and H2O/H3PO4, which played a critical role in the improvement of the conductivity of the composite membranes at temperature over 100 ℃. Proton conductivities of H3PO4 doped with 3 wt% SO-POSS contained ABPBI membranes increased with the increase of H3PO4 absorbance, reaching the maximum proton conductivity of 2.55 × 10^-3 S·cm^-1 at 160 ℃, indicating that the ABPBI/SO-POSS composite membrane could be a promising candidate for mid-temperature PEMFCs.

SYNTHESIS, CHARACTERIZATION, METAL-UPTAKE BEHAVIOR OF BIS(BENZIMIDAZOLE) RESIN SUPPORTED ON EPOXIDE POLYMER

The new chelate resins, abbreviated as PNBMZs and PBBMZs based on epoxide polymer, were synthesized by polycondensation of N,N-diglycidyl-4-glycidyloxyaniline or 1,4-bis（2,3-epoxypropyl）benzene with the primary amine group of 1,3-bis（benzimidazol-2yl）propylamine （BBPAH）. The ion exchangers contain 2.71-3.23 mmol of the ligand contents per gram of the resin. Batch extraction capacities were determined for the metal chloride salts in buffer solutions in the pH range from -1 to 6.0. The chelate resins were very selective for Cu^2＋, Zn^2＋, Cd^2＋ in the presence of other divalent transition metal ions. The maximum uptake capacities of PNBMZ （synthetic molar ratio = 1：1.5） under non-competitive condition were found to be 0.94 mmol/g for Cu^2＋ at pH = 2, 1.3 mmol/g for Cd^2＋ at pH = 1 and 1.75 mmol/g for Zn^2＋ at pH = -1 respectively. While in the case of PBBMZ, it was 1.39 mmol/g for Cd〉 at pH = 1. The metal-uptake behaviors for both of them showed strong pH dependence, and their extraction capacities increase with decreasing pH. The uptake of Cu^2＋ by the resin PNBMZs at pH = 1 was found to be rather fast with t1/2 = 18 min. Metal-uptake experiments under competitive conditions also confirm that the chelate resins have a high selectivity for Cu^2＋, Zn^2＋, Cd^2＋ and the contrary pH dependence.

Flexible Bis(benzimidazole)-based Ligands Directed the Structure Characteristics of Coordination Polymers Based on Diphenic Acid Co-ligands:Syntheses, Structures and Properties

Two new coordination polymers [Cu_2(bbim)(dpa)_2(C_2H_5OH)_2](1), [Co(dpa)_2(bbbm)](2)(H_2dpa = diphenic acid, bbim = 1,1?-(1,6-hexanediyl)bis-1H-benzimidazole, bbbm = 1,1?-(1,4-butanediyl)bis-1 H-benzimidazole) constructed from bis(benzimidazole)-based ligands with different lengths and diphenic acid co-ligand have been synthesized under solvothermal conditions.Complex 1 possesses Cu-dpa helical chains. The adjacent chains are connected by the bbim ligands into two-dimensional(2D) 3-connected(63) topology. Differently, the layer structure of 2 was consisted by one-dimensional chains containing alternated 8-and 18-membered rings. Furthermore,the thermal stability and fluorescence property for all crystalline materials have been investigated.

Synthesis, Crystal Structure and Catalytic Properties of a New 2D Nickel(II) Coordination Polymer Based on Flexible Bis(benzimidazole)

A new Ni(II) coordination polymer [Ni(L)2(SCN)2]n(L = 1,4-bis(benzimidazol-1-yl)butane) was synthesized hydrothermally and characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. The title compound crystallizes in the monoclinic system, space group C2/c with a = 9.4760(3), b = 24.0408(8), c = 16.5871(5) A, β = 99.832(3)°, V = 3723.2(2) A3, Z = 4, Dc = 1.348 g/cm3, F(000) = 1576, the final R = 0.0486 and w R = 0.0936 for 2938 observed reflections with I 】 2σ(I) for the complex. Structural analysis shows that the coordination polymer possesses a 2D(4,4) layer structure which is composed of Ni(II) centers bridged by L ligand with two kinds of conformations and further assembled into a 3D supramolecular network via π-π stacking interactions. In addition, the fluorescence and catalytic properties, for the degradation of Congo red, of the complex were investigated.

A new long-side-chain sulfonated poly(2,6-dimethyl-1,4-phenylene oxide)(PPO)/polybenzimidazole(PBI)amphoteric membrane for vanadium redox flow battery

A new amphoteric membrane was prepared by blending long-side-chain sulfonated poly(2,6-dimethyl-1,4-phenylene oxide)(S-L-PPO)and polybenzimidazole(PBI)for vanadium redox flow battery(VRFB)application.An acid-base pair structure formed between the imidazole of PBI and sulfonic acid of S-L-PPO resulted in lowered swelling ratio.It favors to reduce the vanadium permeation.While,the increased sulfonic acid concentration ensured that proton conductivity was still at a high level.As a result,a better balance between the vanadium ion permeation(6.1×10^-9 cm^2·s^-1)and proton conductivity(50.8 m S·cm^-1)in the S-L-PPO/PBI-10%membrane was achieved.The VRFB performance with S-L-PPO/PBI-10%membrane exhibited an EE of 82.7%,which was higher than those of pristine S-L-PPO(81.8%)and Nafion 212(78.0%)at 120 m A·cm^-2.In addition,the S-LPPO/PBI-10%membrane had a much longer self-discharge duration time(142 h)than that of Nafion 212(23 h).

A Lanthanide-transition Metal Coordination Polymer:{[CuEu(Hbidc)_2(H_2O)_4]·H_2O}_n(H_3bidc=1H-benzimidazole-5,6-dicarboxylic Acid)

The title complex 1,{[CuEu（Hbidc）2（H2O）4]·H2O}n（H3bidc = 1H-benzimidazole-5,6-dicarboxylic acid）,has been solvothermally synthesized and structurally characterized by single-crystal X-ray diffraction.Complex 1 crystallizes in triclinic,space group P1,with a = 7.791（2）,b = 12.058（3）,c = 12.109（3）,α = 82.189（5）,β = 72.407（5）,γ = 89.184（4）°,V = 1073.7（5）3,C18H18CuEuN4O13,Mr = 713.86,Dc = 2.208 g/cm3,μ（MoKα） = 3.967 mm-1,F（000） = 700,GOOF = 0.950,Z = 2,the final R = 0.0531 and wR = 0.1068 for I 2σ（I）.Complex 1 possess a tape-like chain structure consisting of Eu2C8O4 and Cu2Eu2C18N4O4 metallic rings alternatively arranged and is the first 3d-4f heterometallic complex based on the 1H-ben-zimidazole-5,6-dicarboxylato ligand（Hbidc）.Plenty of hydrogen-bonding and π...π stacking interactions connect the 1D chains to construct a 3D supramolecular architecture.

Synthesis and Luminescence Properties of Three High-dimensional Coordination Polymers:Zn(Ⅱ) with Imidazole or Benzimidazole Ligand

A novel 2D coordination polymer [Zn2（bim）4]n（1）（Hbim=benzimidazole） based on dihydrated- [N,N＇-bis（2-aminophenl）-oxalamide]（L1·2H2O） with zinc nitrate has been synthesized. Previously we have synthesized complexes [In：Zn3（im）12]n（2）（Him= imidazole） and [Zn（im）2]n（3） successfully. In complex 1, each Zn（Ⅱ） coordinated with four ligands adopts a distorted tetrahedron coordination mode, and the 2D grid structure is built by the Zn（bim）4 as the secondary building unit（SBU）. The luminescence properties of the three complexes were investigated for the first time. The emissions with maxima for complexes 1, 2 and 3 are at 379, 469 and 392 nm, respectively.

Hydrothermal Synthesis and Crystal Structure of a New 2D Layered Cadmium(II) Coordination Polymer:[Cd(bimc)_2]_n(bimc=1H-Benzimidazole-5-carboxylate)

A new coordination polymer [Cd（bimc）2]n was obtained by the reaction of Hbimc with Cd（NO3） 2·4H2O in NaOH solution, and characterized by elemental analysis, IR and singlecrystal X-ray diffraction. The crystal belongs to orthorhombic, space group Pbcn with a = 12.533（4）, b = 15.705（5）, c = 15.200（5） A, V= 2991.8（15） A^3, Mr = 434.68, Z = 8, Dc = 1.930 g/cm^3, F（000） = 1712,μ（MoKa） = 1.492 mm^-1, the final R = 0.0410 and wR = 0.0804 for 1661 observed reflections （I 〉 2σ（I））. The Cd atom exhibits a distorted six-coordinate CdNzOa octahedral coordination geometry. The complex molecules are linked by both μ2-（η2-O, O^-）, NI and μ2-（η2-O, O^-）, N3 coordination modes of ligands to form cross-like wave （4, 4） layer structures which are further stacked through interlayer hydrogen bonds and π-π stacking interactions in an offset fashion to form a 3D supramolecular structure.

Synthesis and Crystal Structure of catena-Poly[bis-(benzimidazole)cobalt(II) μ-Phthalato]

The title polymeric complex [Co（C8H4O4）（C7H6N2）2]n has been prepared and its crystal structure was determined by X-ray diffraction method. The crystal belongs to monoclinic, space group C2/c with a=7.7865（12）, b=20.4215（18）, c=13.4880（14）A°,β=103.298（2）°, V=2087.3（4）A°^3, Mr=459.32, Z=4, Dc=1.462 g/cm^3,μ=0.859 mm^-1, F（000）=940, R=0.0636 and wR=0.1639 for 1278 observed reflections （I〉2σ（I））. The complex assumes a distorted tetrahedral coordination geometry, formed by two phthalate anions and two benzimidazoles （bzim）. The phthalate anions bridge the neighboring Co（Ⅱ） atoms to form the polymeric chains. The centroid distance of 3.471（3）A° between the parallel bzim rings of adjacent polymeric chains suggests the existence of π-π stacking.

4天香烟烟雾暴露联合poly(I:C)刺激对小鼠肺部免疫应答及干扰素表达的影响

目的:探讨短期香烟烟雾暴露联合poly(I:C)刺激对小鼠肺部免疫应答及干扰素表达的影响。方法:BALB/c小鼠随机分为4组:对照组、熏烟组、poly(I:C)组和熏烟联合poly(I:C)组。检测支气管肺泡灌洗液(BALF)中总细胞数及细胞分类计数;普通光镜下观察各组细胞形态;荧光定量PCR检测肺组织细胞因子、趋化因子和干扰素及干扰素刺激基因表达。结果:与对照组相比,熏烟联合poly(I:C)组总细胞数计数、巨噬细胞与中性粒细胞计数明显升高(P<0.05),且熏烟联合poly(I:C)组巨噬细胞计数高于poly(I:C)组;与poly(I:C)组比较,熏烟联合poly(I:C)组小鼠气道灌洗液巨噬细胞体积较大,呈圆形或不规则形,细胞质较多空泡;与对照组相比,熏烟联合poly(I:C)组小鼠肺组织中性粒细胞趋化因子CXCL1(P<0.05)、CXCL2(P<0.01)和淋巴细胞趋化因子CCL2(P<0.01)mRNA表达升高,肺组织IL-1β、IL-6、TNF-αmRNA表达明显升高(P<0.01),肺组织IFN-β(P<0.01)、IFN-γ(P<0.05)、MX2(P<0.01)和IP-10(P<0.01)表达显著升高,且与poly(I:C)组小鼠相比,熏烟联合poly(I:C)组小鼠肺组织CXCL2(P<0.05)、TNF-α(P<0.01)和IFN-β(P<0.05)mRNA表达明显升高。结论:熏烟联合poly(I:C)诱导了小鼠肺部炎症反应和干扰素及干扰素刺激基因表达。同时,香烟暴露加剧了poly(I:C)诱导的小鼠肺部急性炎症反应和Ⅰ型干扰素表达。

Syntheses, Crystal Structures, and Properties of Two New Lanthanide Coordination Polymers Constructed from Benzimidazole-5,6-dicarboxylic Acid

Two lanthanide coordination polymers, {[Ln（Hbidc）（bidc）（H2 O）3]·3 H2 O}n（H3 bidc = benzimidazole-5,6-dicarboxylic acid, Ln = Eu（1）, Sm（2）） have been hydrothermally synthesized. Both compounds are isostructure and crystallize in the P21/c space group of monoclinic system. Complex 1: a = 11.087（6）, b = 8.972（5）, c = 23.064（13） ?, b = 95.027（5）o, V = 2285.4（2） ?3, Z = 4, Mr = 669.35, Dc = 1.945 g/cm3, F（000） = 1328, S = 1.044, μ = 2.827 mm-1, R = 0.0393 and wR = 0.0801 for 3458 observed reflections（I > 2s（I））. Complex 2: a = 11.087（6）, b = 8.972（5）, c = 23.064（13） ?, b = 95.027（5）°, V = 2285.4（2） ?3, Z = 4, Mr = 667.74, Dc = 1.941 g/cm3, F（000） = 1324, S = 1.071, μ = 2.652 mm-1, R = 0.0329 and wR = 0.0809 for 3744 observed reflections（I > 2s（I））. Complexes 1 and 2 have been determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectroscopy, and thermogravimetric analyses（TGA）. The single-crystal X-ray diffraction analysis reveals that complexes 1 and 2 are the isostructural 1 D zigzag chain structures, which are further extended into a 3 D supramolecular structure through hydrogen bonds and p···p stacking interactions. Furthermore, the thermal stability, UV-vis absorption spectra and fluorescent properties of complexes 1 and 2 have been investigated and discussed in detail.

Stable Cycling of All-Solid-State Lithium Metal Batteries Enabled by Salt Engineering of PEO-Based Polymer Electrolytes

Poly(ethylene oxide)(PEO)-based polymer electrolytes show the prospect in all-solid-state lithium metal batteries;however,they present limitations of low room-temperature ionic conductivity,and interfacial incompatibility with high voltage cathodes.Therefore,a salt engineering of 1,1,2,2,3,3-hexafluoropropane-1,3-disulfonimide lithium salt(LiHFDF)/LiTFSI system was developed in PEO-based electrolyte,demonstrating to effectively regulate Li ion transport and improve the interfacial stability under high voltage.We show,by manipulating the interaction between PEO matrix and TFSI^(-)-HFDF^(-),the optimized solid-state polymer electrolyte achieves maximum Li+conduction of 1.24×10^(-4)S cm^(-1)at 40℃,which is almost 3 times of the baseline.Also,the optimized polymer electrolyte demonstrates outstanding stable cycling in the LiFePO_(4)/Li and LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)/Li(3.0-4.4 V,200 cycles)based all-solid-state lithium batteries at 40℃.

Flexible and Robust Functionalized Boron Nitride/Poly(p‑Phenylene Benzobisoxazole)Nanocomposite Paper with High Thermal Conductivity and Outstanding Electrical Insulation

With the rapid development of 5G information technology,thermal conductivity/dissipation problems of highly integrated electronic devices and electrical equipment are becoming prominent.In this work,“high-temperature solid-phase&diazonium salt decomposition”method is carried out to prepare benzidine-functionalized boron nitride(m-BN).Subsequently,m-BN/poly(pphenylene benzobisoxazole)nanofiber(PNF)nanocomposite paper with nacremimetic layered structures is prepared via sol–gel film transformation approach.The obtained m-BN/PNF nanocomposite paper with 50 wt%m-BN presents excellent thermal conductivity,incredible electrical insulation,outstanding mechanical properties and thermal stability,due to the construction of extensive hydrogen bonds andπ–πinteractions between m-BN and PNF,and stable nacre-mimetic layered structures.Itsλ∥andλ_(⊥)are 9.68 and 0.84 W m^(-1)K^(-1),and the volume resistivity and breakdown strength are as high as 2.3×10^(15)Ωcm and 324.2 kV mm^(-1),respectively.Besides,it also presents extremely high tensile strength of 193.6 MPa and thermal decomposition temperature of 640°C,showing a broad application prospect in high-end thermal management fields such as electronic devices and electrical equipment.

A Two-dimensional Coordination Polymer of Manganese(II) and Benzimidazole-5,6-dicarboxylate

A new two-dimensional （2D） manganese（II） coordination polymer {[Mn（bidc）（H2O）2]· 2H2O}n （H2bidc = benzimidazole-5,6-dicarboxylic acid） was synthesized, and characterized by X-ray crystallography and other measurements. The complex crystallizes in the orthorhombic system, space group Pbca with a = 7.0218（7）, b = 17.9701（18）, c = 19.0697（19）, V = 2406.3（4）3, Z = 8, Dc = 1.823 g/cm3, Mr = 330.14, F（000） = 1344, μ（MoKα） = 1.140 mm-1, S = 1.055, R = 0.0305 and wR = 0.1012 for 2130 observed reflections （I 2σ（I））. The title complex consists of a novel 2D network with a topology of short symbol （4.82）（4.82）.

Innovative approach to boosting the chemical stability of AZ31 magnesium alloy using polymer-modified hybrid metal oxides

Meeting the demands of complex and advanced applications requires the development of high-performance hybrid materials with unique properties.However,the integration of polymeric frameworks with MgO/WO_(3) composite layers faces challenges due to the lack of understanding of the formation mechanism and the challenge of determining the impact of self-assembled architecture on anticorrosive properties.In this study,we aimed to enhance the corrosion resistance of the MgO layer produced by plasma electrolysis(PE)of AZ31 Mg alloy by incorporating WO_(3) with partially phosphorated poly(vinyl alcohol)(PPVA).Two types of porous MgO layers were produced using the PE process with an alkaline-phosphate electrolyte,one with and one without WO_(3) nanoparticles,which were subsequently immersed in an aqueous solution of PPVA.Incorporating PPVA into the WO_(3)-MgO layer resulted in hybrids being deposited in a fragmented manner,creating a“laminar reef-like structure”that sealed most of the structural defects in the layer.The PPVA-sealed WO_(3)-based coating exhibited superior corrosion resistance compared to the other samples.Computational analyses were employed to explore the mechanism underlying the formation of PPVA/WO_(3) hybrids on the MgO layer.These findings suggest that PPVA-WO_(3)-MgO hybrid coatings can potentially improve corrosion resistance in various fields.

Dual-salt poly(tetrahydrofuran) electrolyte enables quasi-solid-state lithium metal batteries to operate at -30 ℃

The stable operation of solid-state lithium metal batteries at low temperatures is plagued by severe restrictions from inferior electrolyte-electrode interface compatibility and increased energy barrier for Li^(+)migration.Herein,we prepare a dual-salt poly(tetrahydrofuran)-based electrolyte consisting of lithium hexafluorophosphate and lithium difluoro(oxalato)borate(LiDFOB).The Li-salt anions(DFOB−)not only accelerate the ring-opening polymerization of tetrahydrofuran,but also promote the formation of highly ion-conductive and sustainable interphases on Li metal anodes without sacrificing the Li^(+)conductivity of electrolytes,which is favorable for Li^(+)transport kinetics at low temperatures.Applications of this polymer electrolyte in Li||LiFePO_(4)cells show 82.3%capacity retention over 1000 cycles at 30℃and endow stable discharge capacity at−30℃.Remarkably,the Li||LiFePO4 cells retain 52%of their room-temperature capacity at−20℃and 0.1 C.This rational design of dual-salt polymer-based electrolytes may provide a new perspective for the stable operation of quasi-solid-state batteries at low temperatures.

Tuning the cross-linked structure of basic poly(ionic liquid)to develop an efficient catalyst for the conversion of vinyl carbonate to dimethyl carbonate

Dimethyl carbonate(DMC)is a crucial chemical raw material widely used in organic synthesis,lithiumion battery electrolytes,and various other fields.The current primary industrial process employs a conventional sodium methoxide basic catalyst to produce DMC through the transesterification reaction between vinyl carbonate and methanol.However,the utilization of this catalyst presents several challenges during the process,including equipment corrosion,the generation of solid waste,susceptibility to deactivation,and complexities in separation and recovery.To address these limitations,a series of alkaline poly(ionic liquid)s,i.e.[DVBPIL][PHO],[DVCPIL][PHO],and[TBVPIL][PHO],with different crosslinking degrees and structures,were synthesized through the construction of cross-linked polymeric monomers and functionalization.These poly(ionic liquid)s exhibit cross-linked structures and controllable cationic and anionic characteristics.Research was conducted to investigate the effect of the cross-linking degree and structure on the catalytic performance of transesterification in synthesizing DMC.It was discovered that the appropriate cross-linking degree and structure of the[DVCPIL][PHO]catalyst resulted in a DMC yield of up to 80.6%.Furthermore,this catalyst material exhibited good stability,maintaining its catalytic activity after repeated use five times without significant changes.The results of this study demonstrate the potential for using alkaline poly(ionic liquid)s as a highly efficient and sustainable alternative to traditional catalysts for the transesterification synthesis of DMC.

Efficient and selective upcycling of waste polylactic acid into acetate using nickel selenide

The conversion of waste polylactic acid(PLA)plastics into high-value-added chemicals through electrochemical methods is a promising and sustainable approach.However,developing efficient and highly selective catalysts for lactic acid oxidation reaction(LAOR)and understanding the reaction process are challenging.Here,we report the electrooxidation of waste PLA to acetate at a high current density of 100 mA cm-2 with high Faraday efficiency(~95%)and excellent stability(>100 h)over a nickel selenide nanosheet catalyst.In addition,a total Faraday efficiency of up to 190%was achieved for carboxylic acids,including acetic acid and formic acid,by coupling with the cathodic CO_(2) reduction reaction.In situ experimental results and theoretical simulations revealed that the catalytic activity center of LAOR was dynamically formed NiOOH species,and the surface-adsorbed SeO_(x) species accelerated the formation of Ni~(3+)species,thus promoting catalytic activity.The mechanism of lactic acid electrooxidation was further elucidated.Lactic acid was dehydrogenated to produce pyruvate first and then formed CH_3CO due to preferential C-C bond cleavage,resulting in the presence of acetate.This work demonstrated a sustainable method for recycling waste PLA and CO_(2) into high-value-added products.

TOPCon太阳电池背面叠层poly工艺的优化及其对电性能的影响

通过增加TOPCon太阳电池poly层中的磷掺杂浓度可以增强poly层与硅基底之间的钝化效果并提高poly层与金属电极间的接触能力,但过高的掺杂浓度会导致磷原子扩散到硅基底,破坏氧化层与硅基底之间的界面钝化效果。为了解决这一问题,提出在poly层中间增加一层薄的氧化层作为阻挡层(即叠层poly工艺,下文简称为“叠层工艺”)的方案,将原本单一的poly-Si磷掺杂进行双层分布,底层poly-Si轻掺杂,表层poly-Si重掺杂;对常规工艺和叠层工艺制备TOPCon的太阳电池进行对比试验后,进一步优化叠层工艺,调整中间氧化层厚度,并研究不同中间氧化层厚度的叠层工艺对TOPCon太阳电池电性能的影响。实验结果表明:1)叠层工艺可以提高TOPCon太阳电池的电性能;2)当中间氧化层厚度提升至1.5 nm时,太阳电池的光电转换效率达到最高值(25.66%)。但中间氧化层的厚度是一个需要精确控制的工艺参数,需找到最佳的厚度平衡点,以提高太阳电池性能。