Investigation of La_(9.33)Si_6O_(26) Oxygen Ionic Conductor

La9.335i6O26 oxygen ionic conductor was synthesized by solid state reaction method. Its structure was deter- mined by single-crystal X-ray diffraction analysis at room temperature. The results showed that La9.33Si6O26 oxide has the apatite structure with space group P63/m. AC impedance measurements indicated that the oxides sintered in nitrogen have much higher conductivity than those sintered in air. The effects of grain boundaries on the conductivity were discussed.

Synthesis and Conductivity of Oxyapatite Ionic Conductor La10-xVx（SiO4）6O3＋x

Apatite-lanthanum silicate has attracted considerable interest in recent years due to its high oxide ion conductivity.In this paper,V-doped samples La10-xVx(SiO4) 6O3+x(0≤x≤1.5) were prepared by sol-gel method and the influences of V-dopant content on calcining temperature and conductivity were reported.The samples were characterized by thermal analysis(TG-DSC) ,X-ray diffraction(XRD) and scanning electron micrograph(SEM) . The apatite was obtained at 800°C,a relatively low temperature in comparison to 1500°C with the conventional solid-state method.The ceramic pellets sintered at 1200°C for 5 h showed a higher relative density than La9.33Si6O26 pellets sintered at 1400°C for 20 h.The conductivities of samples were measured by electrochemical impedance spectroscopy.The conductivity was improved with the increase of V-dopant content on La site.

Two-dimensional equations for thin-films of ionic conductors

A theoretical model is developed for predicting both conduction and diffusion in thin-film ionic conductors or cables. With the linearized Poisson-Nernst-Planck(PNP)theory, the two-dimensional(2D) equations for thin ionic conductor films are obtained from the three-dimensional(3D) equations by power series expansions in the film thickness coordinate, retaining the lower-order equations. The thin-film equations for ionic conductors are combined with similar equations for one thin dielectric film to derive the 2D equations of thin sandwich films composed of a dielectric layer and two ionic conductor layers. A sandwich film in the literature, as an ionic cable, is analyzed as an example of the equations obtained in this paper. The numerical results show the effect of diffusion in addition to the conduction treated in the literature. The obtained theoretical model including both conduction and diffusion phenomena can be used to investigate the performance of ionic-conductor devices with any frequency.

Na3.8[Sn0.67Si0.33]0.8Sb0.2S4:A quinary sodium fast ionic conductor for all-solid-state sodium battery

Strategy of Sb-substitution is carried out on the template structure Na4Sn0.67M0.33S4(M=Si,Ge),which affords a series of quinary sulfide-based sodium fast ionic conductors formulated as Na4-x[Sn0.67M0.33]1-xSbxS4(M=Si,x=0.1,0.2,0.3;M=Ge,x=0.2.).Among them,the highest ambient ionic conductivity(1.75×10^-4 S cm^-1)is achieved when M=Si and x=0.2.The new fast ionic conductor Na3.8[Sn0.67Si0.33]0.8Sb0.2S4 is isostructural to its structure template Na4Sn0.67Si0.33S4 and thus crystallizes in the space group of I41/acd.It is shown that the incorporation of Sb improves the ionic conductivity.The study of lattice parameters shows that the improvement of the ion conductivity by Sbsubstitution is mainly due to the enlarged crystal lattice.Furthermore,using Na3.8[Sn0.67Si0.33]0.8Sb0.2S4as solid electrolytes,room temperature all-solid-state sodium battery of Se0.05S0.95@pPAN/Na3Sn is realized,which proves the novel fast ionic conductor a potential candidate to apply in sodium solid state battery.This work not only extends the scope of Na4[Sn0.67Si0.33]S4,the I41/acd space group template,but also deepens the understanding of the lattice size effect on the structure and property relationship by aliovalent substitution.

STUDY ON THE STRUCTURE OF IONIC CONDUCTOR FOR LiH-LiF-P_2O_5 GLASS SYSTEM

The system of LiH-LiF-P_2O_5 ionic conductor glass is prepared in neutral atmosphere and glass -forming region is given. The structure and coor- dination of glass are analyzed by IR spectra. Raman spectra and RDF(r). The result indicates that the (PO_4), (PO_3F) and (LiF_4) tetrahedra are basical structure units of glass network and the coordina- tion number of Li is 4. The coordination number of P is 4. The glass random network structure model is given. The study on structure shows that Li^+, H^- and partial F^- are charge carriers in glass system.

IONIC CONDUCTION MECHANISM IN Na_(5+x)YA1_xSi_(4-x)O_(12) SUPERIONIC CONDUCTORS

Na_(5+x) YAl_x Si_(4-x) O_(12) polycrystalline solid electrolytes are prepared by solid reactions. By the analyses of X-ray, TG and DTA, infrared spectu re, and SEM, the variasion of their density with the composition X are discussed Their electric conductivity in the temperature range of R. T. to 300℃ are determined with electric brigde, and their variasions with the compositions X and temperature are studied. Their activations in the tem- perature range 140℃ to 300℃ are calculated, and their variation with the compositons X are discussed.

Li-and Mg-based borohydrides for hydrogen storage and ionic conductor

LiBH_(4) and Mg(BH_(4))_(2) with high theoretical hydrogen mass capacity receive significant attentions for hy-drogen storage.Also,these compounds can be potentially applied as solid-state electrolytes with their high ionic conductivity.However,their applications are hindered by the poor kinetics and reversibility for hydrogen storage and low ionic conductivity at room temperature,respectively.To address these challenges,effective strategies towards engineering the hydrogen storage properties and the emerging solid-state electrolytes with improved performances have been summarized.The focuses are on the state-of-the-art developments of Li/Mg-based borohydrides with a parallel comparison of similar methods ap-plied in both hydrogen storage and solid-state electrolytes,particularly on the phase,structure,and thermal properties changes of Li/Mg-based borohydrides induced by milling,ion substitution,coordination,adding additives/catalysts,and hydrides.The similarities and differences between the strategies towards two kinds of applications are also discussed and prospected.The review will shed light on the future development of Li/Mg-based borohydrides for hydrogen storage and solid-state electrolytes.

Molecular coordination-doping engineering enables adjustable ion transport channel based on MOFs-derived UIOLiTF-LLZTO ionic conductor

The inferior ionic conductivity of composite polymer electrolytes(CPEs)caused by grain boundary impedance is one of the critical issues.Adjustable ion transport channels at the molecular level can improve ionic conductivity and lithium-ion transference number.Herein,UIO-66-NSO_(2)CF_(3)LiLi_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(UIOLiTF-LLZTO)ionic conductor derived from metal-organic frameworks(MOFs)was designed by a covalent grafted strategy of trifluoromethylsulfonyl(TF)group on UIOLiTF and a doping process of LLZTO,showing two new lithium-ion transfer channels driven by molecular coordinationdoping engineering.The first channel along UIOLiTF-UIOLiTF was constructed due to the existence of the TF group on UIOLiTF.The second channel along UIOLiTF-LLZTO was constructed due to the direct nanometer contact interface between the opened channel of UIOLiTF and LLZTO.Then TF group acts as“claws”to capture and transfer lithium-ion along the different channels,facilitating improving ionic conductivity and reducing grain boundary impedance.Benefiting from the molecular coordination-doping engineering,UIOLiTF-LLZTO exhibits high ionic conductivity of 9.86×10^(-4)S cm^(-1),a large lithium-ion transference number of 0.79,and a wide electrochemical window of 5.35 V.Meanwhile,all-solid-state Li|UIOLiTF-LLZTO|LiFePO4 batteries show a high specific capacity of 164.5 mAh g^(-1)and 155.6 mAh g^(-1)at 0.2 C and 0.5 C,respectively.Therefore,UIOLiTF-LLZTO demonstrates the way towards the development of MOFs-based CPEs for all-solid-state lithium batteries with high performance.

Highly Stretchable,Elastic,Healable,and Ultra-Durable Polyvinyl Alcohol-Based Ionic Conductors Capable of Safe Disposal

Highly durable and stretchable ionic conductors are indispensable components of flexible electronics.However,fabricating such ionic conductors that are also non-toxic and biodegradable remains a challenge.In this study,highly stretchable,elastic,healable,and ultra-durable ionic conductors capable of non-hazardous disposal are conveniently fabricated by complexation of vanillin-grafted polyvinyl alcohol(VPVA)and ionic liquids(ILs)(denoted as VPVA-IL).

Electrical properties of garnet-like lithium ionic conductors Li5＋xSrxLa3-xBi2O12 fabricated by spark plasma sintering method

A typical approach involving Pechini method and spark plasma sintering （SPS） method was presented for the preparation of high density Li5＋xSrxLa3_xBi2012 （x = 0, 1） ceramics. Phase formation, microstructure, grain size and electrical properties of the specimens were examined using XRD, SEM and alternating current impedance spectro- scopy （ACIS）. Dense LisLa3Bi2012 and LisSrLa2Bi2012 ceramics with pure garnet-like phase, relative density of 97% and average grain size of about 5 pm were fabricated using this approach. The total conductivities at 298 K of Li5La3Bi2012 and LisSrLa2Bi2O12 ceramics prepared by the SPS method are 5.1 Qian-Feng FANG105 and 6.810SS/cm, respectively, 2 times higher than that of samples prepared by the conventional sintering method.

Novel fast ionic conductor ceramic composite separator for highperformance safe Li-ion power batteries

The ceramic composite separators coated with silica or alumina particles have been used in power batteries due to their better electrolyte wettability and better thermal stability compared with bare polymer separators.However,these oxide ceramics are Liþion insulators,which increase internal resistance and hinder the improvement of rate capability of batteries.Herein,we report a strategy to further improving the performance of lithium-ion batteries(LIBs)by using fast ionic conductor ceramic composite separator as an alternative to traditional ceramic coated separators.Lithium lanthanum titanate(LLTO),a fast ionic conductor with excellent room temperature bulk conductivity,are coated on the common polyethylene(PE)separators.Our results demonstrate that such a novel LLTO-coated separator possess excellent electrolyte wettability and thermal stability;and the assembled NCM523/graphite lithium-ion pouch cells with LLTO-coated separator show better rate capability and cyclic performance with 88.7%capacity retention after 1000 cycles at room temperature compared with the pouch cells with Al2O_(3)-coated separators.The fast ionic conductor ceramic composite separators will be a potential competitor to the next-generation novel separators for high-performance Li-ion power batteries.

LITHIUM IONIC CONDUCTORS OF Rc STRUCTURE

Due to its low electronegativity and light weight, if lithium is used as negative electrode material for electrochemical devices, the cell voltage and energy density may be enhanced. In recent years, the search for a new lithium conductor increased obviously with the increasing interest in all solid state lithium cell. LISICON is a three-dimensional lithium conductor with high conductivity, but its chemical stability is not good, and its conductivity at room temper-

Laser melted hypereutectoid ZrO2-MgO fast ionic conductor

The cubic and/or tetragonal ZrO2 solid solution polycrystalline ceramics obtained byaddition of appropriate amounts of oxides asCaO, Y2O3, MgO or rare earth oxides to zirconiahas ioinc conductivity and is used as fast ionicconductor for new ceramic fuel cells and sensors.For MgO-stabilized zirconia the MgO content

Development of proton-conducting membrane based on incorporating a proton conductor 1,2,4-triazolium methanesulfonate into the Nafion membrane

In this paper, 1,2,4-triazolium methanesulfonate （C_2H_4N_3^＋-CH_3SO_3^-, [Tri][MS]）, an ionic conductor, was successfully synthesized. It exhibited high ionic conductivity of 18.60 mS·cm^-1 at 140 ℃ and reached up to 36.51 mS·cm^-1 at 190 ℃. [Tri][MS] was first applied to modify Nation membrane to fabricate [Tri][MS]/Nafion membrane by impregnation method at 150 ℃. The prepared composite membrane showed high thermal stability with decomposed temperature above 200 ℃ in air atmosphere. In addition, the membrane indicated good ionic conductivity with 3.67 mS·cm^-1 at 140 ℃ and reached up to 13.23 mS·cm^-1 at 180 ℃. The structure of the [Tri][MS] and the composite membrane were characterized by FTIR and the compatibility of [Tri][MS] and Pt/C catalyst was studied by a cyclic voltammetry （CV） method. Besides, the [Tri][MS]/Nafion membrane （thickness of 65 μm） was evaluated with single fuel cell at high temperature and without humidification. The highest power density of [Tri][MS]/Nafion membrane was 3.20 mW·cm^-2 at 140 ℃ and 4.90 mW·cm^-2 at 150 ℃, which was much higher than that of Nation membrane.

单离子导体型聚合物电解质的研究进展

研发一种具有高能量密度、更长循环寿命和更高安全性的固态锂电池,是近几年为下一代电池设定的主要目标之一。传统液态电解质存在易燃、易泄露等缺陷,限制了其在锂离子电池中的应用。聚合物电解质具有更高的安全性能,兼具高可加工性、高柔韧性、低可燃性以及宽电化学窗口等优势,有望替代液态电解质,并在下一代高能量密度储能装置中极具应用潜能。与传统双离子导体聚合物电解质(DICPEs)相比,单离子导体型聚合物电解质(SICPEs)具有高的离子迁移数(tLi+接近1),可有效避免浓差极化的形成,抑制锂枝晶生长。文中总结了近几年SICPEs体系的研究进展,梳理了合成方法、分子结构设计,分析了当前单离子导体体系的主要挑战,并对未来该领域的发展方向进行了展望,为锂离子电池用单离子导体的研究提供技术创新方面的启发。

Forming solid electrolyte interphase in situ in an ionic conducting Li_(1.5)Al_(0.5)Ge_(1.5)(PO_4)_3-polypropylene(PP) based separator for Li-ion batteries

A new concept of forming solid electrolyte interphases（SEI） in situ in an ionic conducting Li（1.5）Al（0.5）Ge（1.5）（PO4）3-polypropylene（LAGP-PP） based separator during charging and discharging is proposed and demonstrated. This unique structure shows a high ionic conductivity, low interface resistance with electrode, and can suppress the growth of lithium dendrite. The features of forming the SEI in situ are investigated by scanning electron microscopy（SEM） and x-ray photoelectron spectroscopy（XPS）. The results confirm that SEI films mainly consist of lithium fluoride and carbonates with various alkyl contents. The cell assembled by using the LAGP-coated separator demonstrates a good cycling performance even at high charging rates, and the lithium dendrites were not observed on the lithium metal electrode. Therefore, the SEI-LAGP-PP separator can be used as a promising flexible solid electrolyte for solid state lithium batteries.

Correlation between hydration properties and electrochemical performances on Ln cation size effect in layered perovskite for protonic ceramic fuel cells

PrBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(PrBSCF) has attracted much research interest as a potential triple ionic and electronic conductor(TIEC) electrode for protonic ceramic fuel cells(PCFCs). The chemical formula for Pr BSCF is AA'B_(2)O_(5+δ), with Pr(A-site) and Ba/Sr(A'-site) alternately stacked along the c-axis. Due to these structural features, the bulk oxygen ion diffusivity is significantly enhanced through the disorder-free channels in the PrO layer;thus, the A site cations(lanthanide ions) play a pivotal role in determining the overall electrochemical properties of layered perovskites. Consequently, previous research has predominantly focused on the electrical properties and oxygen bulk/surface kinetics of Ln cation effects,whereas the hydration properties for PCFC systems remain unidentified. Here, we thoroughly examined the proton uptake behavior and thermodynamic parameters for the hydration reaction to conclusively determine the changes in the electrochemical performances depending on LnBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(LnBSCF,Ln=Pr, Nd, and Gd) cathodes. At 500 ℃, the quantitative proton concentration of PrBSCF was 2.04 mol% and progressively decreased as the Ln cation size decreased. Similarly, the Gibbs free energy indicated that less energy was required for the formation of protonic defects in the order of Pr BSCF < Nd BSCF < Gd BSCF. To elucidate the close relationship between hydration properties and electrochemical performances in LnBSCF cathodes, PCFC single cell measurements and analysis of the distribution of relaxation time were further investigated.

基于NCO-YSZ半导体-离子导体复合电解质导电率探究

导电率作为验证材料属性的关键步骤,具有十分关键的作用,如助力研究人员了解材料导电性能的同时反映材料内部的结构和缺陷,继而让其更好地对材料进行评估或更有针对性地应用。在此基础上,将研究复合离子导体YSZ与P型半导体Na_(x)CoO_(2),所得到NCO-YSZ半导体-离子导体复合电解质的导电率,为对相关人员降低YSZ基SOFC的操作温度,增加中低温区离子传导率,提供一定思路。

IONIC CONDUCTIVITIES OF SEGMENTED POLYETHER POLYURETHANEUREA COMPLEXES WITH LiClO_4

Ionic conductivity values for segmented polyether polyurethaneurea (PEUU) complexes with LiClO_4 were determined and values as high as～1.1×10^(-4) S·cm^(-1) at 353K and～1.0×10^(-5)S·cm^(-1) at 306K were achieved. The ionic conductivity data were analyzed using the VTF (Vogel-Tamman-Fulcher) equation and WLF (Williams-Landel-Ferry) type equation. Values have been estimated for the 'apparent' activation energies of ion transport from VTF equation and they lie in the range 2.70—5.53 kJ·mol^(-1).

SINGLE IONIC CONDUCTI0N OF POLYSILOXANE CONTAINING PROPYLENE CARBONATE GROUP AND LITHIUM POLYMERIC SALTS

The polysiloxane containing propylene carbonate side group and several lithium poly-meric salts were synthesized. The structure were confirmed by IR, NMR and XPS. Theblending systems of polysiloxane containing propylene carbonate group with different lithiumpolymeric salts were studied by ion conductivity XPS and DSC. Different lithium poly-meric salts in the blending system lead to conductivity arranged in the following sequence:poly(lithium ethylenebenzene sulfonate methylsiloxane)>poly(lithium propionate methyl-siloxane)>poly(lithium propylsulfonate methylsiloxane)>poly(lithium styrenesulfonate).In the blending system the best single ion conductivity was close to 10^(-5) Scm^(-1) at roomtemperature. XPS showed that at low lithium salt concentration the conductivity increasedwith the increasing content of lithium salt, in consequence of the increase of free ion andsolvent separated ion pair. At high lithium salt concentration the free ion was absent andthe solvent-separated ion pair functioned as carrier.