Solid Electrolyte Films Research Articles

Lithium ion conductivity of oriented Li0.33La0.56TiO3 solid electrolyte films prepared by a sol–gel process

Lithium lanthanum titanates (Li3xLa2/3−xTiO3, LLTOs) having a-axis orientations were synthesized via a simple sol–gel route on SrTiO3 and Nb-doped SrTiO3 substrates. The lithium ion conduction behaviors of the LLTO films were determined. Annealing the films above 1200°C yielded strong a-axis growth orientation, while heating samples above 1300°C led to the reduction of the Li transference number, TLi, which was attributed to Li evaporation. The optimized annealing temperature was 1200°C, where both the bulk conductivity, σdc, and the TLi exhibited their maxima. The bulk conductivity was 4.42×10−5S/cm for a 411-nm-thick film, which was almost 10-times-higher than that previously reported for sol–gel-derived films. A key reason for the enhancement in conductivity is the expanded bottleneck of the LLTO lattice because of a tensile stress induced by the substrate. Optimization of the annealing temperature and the film thickness further improved the conductivity.

Advanced Impedance Spectroscopy Study of the Influence of the Crystalline Structure on the Ionic Conduction of Thin Solid-State Electrolytes

Solid electrolytes exhibit electrical conductivity due to the presence of mobile ions which act as charge carriers through the crystalline structure. For their use in solid oxide fuel cells (SOFCs), a sufficient electrical conductivity is achieved by operating at high temperatures. To reduce the application temperature, research is dedicated to increase the electrical conductivity of the ceramic material otherwise. One way is decreasing the film thickness. Yet, the relationship between the material crystallinity and the ion conductivity may be reinterpreted when reducing the thickness to the micrometer and nanometer scales. Another way is by reducing the grain size. At present it is not clear how the microstructure of solid state electrolytes affect the electrical conduction. In literature, the experiments on nanocrystalline solid oxides yield contradictory observations [1-6]. A good understanding of the relationship between microstructure and ion conductivity would open the possibility to engineer advanced thin materials for solid oxide fuel cells. We propose an experimental and modeling approach that aims at unraveling the electrical behavior of thin film solid state electrolytes, by considering the crystalline nature of the material. Through careful comparison of simulations and measurements we want to explain the observed electrical properties of these materials to predict how their conductivity can be enhanced. In this research, the complex electrical properties at different temperatures of yttrium-doped ceria electrolytes, with different thicknesses and grain sizes, are determined by electrochemical impedance spectroscopy (EIS). The solid oxide is deposited by reactive magnetron sputtering, which allows us to modify the morphology and composition of the thin film in a controlled and flexible way [7]. In the EIS characterization, improved electrode geometry is also searched. Experiments with platinum co-planar electrodes are performed and compared with those with an interdigital electrode structure. The specific electrode geometry is designed by 2D simulations for a solid oxide film in contact with the substrate. A finite element model of the electrical conductivity was recently developed to simulate impedance spectra and electrical conductivities as a function of grain size and temperature [8]. More rigorous than the dilute solution models, it is based on the application of the linear phenomenological relations to a crystal lattice. The impedance modeling provides a description of the electrical behavior of the material. The EIS results are then compared with the ones generated by the finite element model. The combined analysis aims to elucidate the experimental evidence that is not explained by the available physical models. Therefore, it represents a strong approach to understand the electrical properties and ion conduction of solid electrolytes. [1] J. Maier “Ionic conduction in space charge regions”, Progress in Solid State Chemistry 23 (1995) 171–263. [2] J. Maier “Nano-sized mixed conductors (Aspects of nano-ionics. Part III)”, Solid State Ionics 148 (2002) 367–374. [3] X. Guo, R. Waser “Electrical properties of the grain boundaries of oxygen ion conductors: Acceptor-doped zirconia and ceria”, Progress in Materials Science 51 (2006) 151–210. [4] J. Maier “Nanoionics: ionic charge carriers in small systems”, Physical Chemistry Chemical Physics 11 (2009) 3011–3022. [5] C. Peters, A. Weber, B. Butz, D. Gerthsen, E. Ivers-Tiffée “Grain-Size Effects in YSZ Thin-Film Electrolytes”, Journal of the American Ceramic Society 92 (9) (2009) 2017–2024. [6] X. Guo “Can we achieve significantly higher ionic conductivity in nanostructured zirconia?”, Scripta Materialia 65 (2011) 96–101. [7] S. Mahieu, P. Ghekiere, G. De Winter, S. Heirwegh, D. Depla, R. De Gryse., O.I. Lebedev, G. Van Tendeloo “Mechanism of preferential orientation in sputter deposited titanium nitride and yttria-stabilized zirconia layers”, Journal Of Crystal Growth 279 (1-2) (2005) 100-109. [8] D. Van Laethem, A. Hubin, J. Deconinck “Finite element modelling of the electrical conductivity of acceptor doped ceria”, 6th International Conference on Fundamentals and Development of Fuel Cells, 3rd- 5th February, Toulouse (France).

Ionic Conductivity via Quantum Mechanical Tunneling in NH<sub>4</sub>NO<sub>3</sub> Doped Carboxymethyl Cellulose Solid Biopolymer Electrolytes

<p class="TTPSectionHeading">Carboxymethyl cellulose–NH4NO3 solid biopolymer electrolyte films were prepared by solution casting technique. Ammonium nitrate (NH4NO3) with 5–50 wt.% were dissolved in disparate carboxymethyl cellulose (CMC) solution, respectively. The electrical properties and conduction mechanism of electrolyte films have been revealed by employing electrical impedance spectroscopy in the frequency range of 50 Hz to 1 MHz within the temperature range of 303 K to 353 K. The ionic conductivity was observed to be influenced by the NH4NO3 concentration. The conductivity–temperature relationship is Arrhenius. From dielectric loss variation with frequency, the power law exponent was obtained. The temperature dependence of the power law exponent for CMC– NH4NO3 system can be represented by the quantum mechanical tunneling (QMT) model.</p>

Advanced Impedance Spectroscopy Study of the Influence of the Crystalline Structure on the Ionic Conduction of Thin Solid-State Electrolytes

In this work, an experimental and modeling approach that considers the crystalline nature of the material is used to u the electrical behavior of thin film solid state electrolytes. In this research, the complex electrical properties at different temperatures of nanocrystal yttrium-doped ceria (YDC) are determined by electrochemical impedance spectroscopy (EIS). The impedance modeling provides a description of the electrical behavior of the material. The influence of the geometry of the electrodes in the electrical measurements is investigated by finite element simulations for different electrode spacing. The combined analysis represents a strong approach to elucidate the experimental evidence that is not explained by the available physical models.

Bendable and thin sulfide solid electrolyte film: a new electrolyte opportunity for free-standing and stackable high-energy all-solid-state lithium-ion batteries.

Bulk-type all-solid-state lithium batteries (ASLBs) are considered a promising candidate to outperform the conventional lithium-ion batteries. Unfortunately, the current technology level of ASLBs is in a stage of infancy in terms of cell-based (not electrode-material-based) energy densities and scalable fabrication. Here, we report on the first ever bendable and thin sulfide solid electrolyte films reinforced with a mechanically compliant poly(paraphenylene terephthalamide) nonwoven (NW) scaffold, which enables the fabrication of free-standing and stackable ASLBs with high energy density and high rate capabilities. The ASLB, using a thin (∼70 μm) NW-reinforced SE film, exhibits a 3-fold increase of the cell-energy-density compared to that of a conventional cell without the NW scaffold.

Improvement of Power Characteristics of All-Solid-State Thin-Film Rechargeable Lithium Batteries

1. Introduction Recently, all-solid-state thin-film rechargeable lithium batteries (TFBs) has expected in various applications such as wireless sensor, smart device and other small devices for an auxiliary power supply. The TFBs are fabricated by forming each layers (i.e. cathode, electrolyte, anode and current collector) using physical vapor deposition process1,2). As a solid electrolyte, lithium phosphorus oxynitride (LiPON) thin film has been used commonly due to no grain-boundary, isotropic property, less electronic conductivity and electrochemical stability. Ionic conductivity of LiPON thin film has been reported ~3.3 x 10-6 S/cm at 25 deg.C3), but it is lower compared with other solid electrolyte4). It is necessary to reduce the internal resistance of TFBs for applying to the device as described above. In order to improve this, it has to be thinner LiPON film or change the electrolyte material having higher ionic conductivity. However, there is a limited to the thickness of electrolyte film without short- circuit because the surface of cathode film is rougher with thicker cathode film5). In this study, we investigated the planarization of cathode film for thinner electrolyte film. 2. Experimental Lithium cobalt oxide (LCO) film was prepared by RF and DC hybrid power magnetron sputtering method on platinum film as current collector. Ar was used as sputtering gas, and process pressure was kept at 1.6 Pa. Furthermore, LCO was deposited with applying each bias power to the substrate for investigating the planarization. After deposition, LCO was annealed at 600 deg.C under atmospheric pressure by lamp heating system. Solid electrolyte (LiPON) film was prepared by RF magnetron reactive sputtering method with only N2gas. Lithium film as an anode was prepared by vacuum evaporation method. Acrylic monomer as a sealant was coating on the anode surface, covered with barrier lid, and cured by ultraviolet light for encapsulation. The fabricated TFB cells were investigated by electrical and electrochemical properties at room temperature. 3. Results and discussion Figure 1 shows the scanning electron microscopy (SEM) image of 3-μm-thick LCO film under different bias power condition. As the result of this, it was confirmed that surface of LCO becomes smoother with higher bias power and surface morphology changes from pyramid-like to dome-like by re-sputtering. TFB cell was fabricated with 2-μm-thick LiPON and 2-μm-thick lithium and discharge capacity was also checked. The charge method is CCCVmode (current density: 0.21 mA/cm2, cut-off: >4.2 V and <0.021 mA/cm2) and the discharge method is CC mode (current density: 0.21 mA/cm2, cut-off: <3.0 V). Figure 2 shows the discharge curve of TFB cells. It was confirmed that discharge capacity of TFB cell is higher with increasing bias power. It is thought that film density of LCO becomes high due to ion peening effect. The improvement of thinner LiPON film and the other are on evaluating. Reference 1) J. B. Bates, N. J. Dudney, G. R. Gruzalski, R. A. Zuhr, A. Choudhury, C. F. Luck and J. D. Robertson, J. Power Sources, 43, 103 (1993).2) T. Jimbo, P. Kim and K. Suu, Energy Procedia, 14, 1574 (2012).3) Xiaohua Yu, J. B. Bates, G. E. Jellison, Jr., and F. X. Hart, J. Electrochem. Soc., 144, 524 (1997).4) N. Kamaya, K. Homma, Y. Yamakawa, M. Hirayama, R. Kanno, M. Yonemura, T. Kamiyama, Y. Kato, S. Hama, K. Kawamoto and A. Mitsui, Nature Materials, 10, 682 (2011).5) T. Jimbo, S. Sasaki, A. Suzuki, I. Kimura and K. Suu, #1235, 224th ECS Meeting (2013) Figure 1

Preparation and Electrochemical Characterization of Composite Cathodes Prepared By Aerosol Deposition for 5V Class All-Solid-State Lithium Rechargeable Batteries

Introduction Oxide-based all-solid-state batteries (SSBs) are candidates for the next-generation of rechargeable batteries because of their advantages in terms of both high energy density and safety. However, a significant disadvantage of this type of batteries is large contact resistance between active materials and solid electrolytes, which decreases Li+ conductivity in electrodes. To solve this problem, we prepared composite powders of 5V-class active material: LiNi1/2Mn3/2O4 (LNM) and a Li+-conductive solid electrolyte (Ohara Inc. -prepared proprietary composition of Li2O-P2O5-Nb2O5-B2O3-GeO2). We deposited these composite powders on Pt substrates by an Aerosol Deposition (AD) method. AD is a powerful approach to produce composite films at room temperature [1] while suppressing reactions of active materials with solid electrolytes. After preparation, we performed electrochemical measurements of the resultant composite film electrodes. Experimental Composite powders of LNM (Toshima D50=10-15 µm) and Li2O-P2O5-Nb2O5-B2O3-GeO2 solid electrolyte (Ohara Inc.) were prepared by a dry-powder mixer (NOB-MINI, Hosokawa Micron Co.). The mixing ratio of LNM to Li2O-P2O5-Nb2O5-B2O3-GeO2 solid electrolyte was 20:1, weight basis. The obtained composite powders were deposited on Pt substrates by AD to prepare the composite electrodes. Pure LNM powder was also deposited on Pt by AD to compare to the composite electrodes. AD films were characterized by Raman spectroscopy, scanning electron microscopy and energy dispersive X-ray spectrometry (EDX). The amounts of active materials in the composite electrodes were estimated by Image-J image processing software based on cross-sectional-SEM images. Weights of LNM in AD films were estimated by using the volume and density of LNM. In this procedure, we assumed that films were considered fully densified in these estimates. The resultant films were covered by LiPON solid electrolyte films by radio frequency magnetron sputtering. Subsequently, Li anode films were deposited on the top of LiPON films by vacuum evaporation. The characterization studies of fabricated SSBs (Pt | LNM or the composite electrodes | LiPON | Li) included cyclic voltammetry (1.0 mV sec-1), impedance spectroscopy (frequency range: 10 mHz to 500 kHz), and galvanostatic charge-discharge measurements (1.0 μA cm-2). All electrochemical measurements were carried out at 25 °C in an Ar filled glovebox. Results and Discussions The SEM images of the composite powder showed that the solid electrolyte powder uniformly distributed on LNM particle surfaces. In Figure 1, the cross-sectional SEM images of AD films showed that AD films have dense structures, and the thicknesses were more than about 1 μm. In the case of AD films of the composite electrode, LNM and Li2O-P2O5-Nb2O5-B2O3-GeO2solid electrolyte were uniformly distributed with layer-like structures. Nyquist plots at 4.7 V (Li/Li+) showed that the charge transfer resistance was lower for composite cathodes compared to pure LNM cathodes. Figure 2 shows the first charge-discharge curves of SSBs. The SSB with a composite electrode had a specific capacity of 62.7 mAh g-1 which was higher value compared to the SSB with pure LNM electrode (4.3 mAh g-1). Approximately 43% of the theoretical specific capacity of LNM (147 mAh g-1) could be obtained by fabricating the composite electrolyte. It is thought that Li2O-P2O5-Nb2O5-B2O3-GeO2 solid electrolyte filled in space among the LNM particles produce Li+conductive pathways, which increased the amounts of effective active materials, and reduced apparent resistance. In this way, the discharge capacity for the composite electrodes increased. Conclusion As a result, for electrodes fabricated by an AD technique, the composite electrodes had lower charge transfer resistance and higher discharge capacity compared to pure LNM electrodes. Acknowledgement This work is financially supported by NEDO-Post LiEAD. Figure 1

Fabrication and Characterization of Dysprosium‐Doped Bismuth Oxide Films for IT‐SOFCs via Slurry Spin Coating Technique

The production and stabilization of the fcc‐phase Bi2O3 solid solution (δ‐DSB) in the binary system of (Bi2O3)1−x(Dy2O3)x have been investigated in the doping range of 0.10 ≤ x ≤ 0.25 by adding Dy2O3 into pure α‐Bi2O3. All δ‐DSB samples were stabilized and exhibited single δ‐phase at 800°C. Thick film solid electrolytes were produced by the spin coating method. All of the coating and sintering parameters were optimized. Crystallographic, microstructural, and electrical characterizations were made for the produced films. The highest value of conductivity was ~1–10 Scm−1 for 11–15 mol% δ‐DSB film samples. The electrical conductivity curves of samples showed regular increase.

Effects of protons within SiO2 solid-state electrolyte on performances of oxide electric-double-layer thin film transistor

SiO2-based solid state electrolyte films are deposited at room temperature by using the plasma-enhanced chemical vapor deposition (PECVD) technique. An electric-double-layer (EDL) effect has been observed. Then, indium-zinc-oxide thin-film transistors (IZO TFTs) are fabricated by using such SiO2 films as dielectrics in a self-assembling process through a shadow mask. The IZO films for source/drain electrodes and channel are deposited on the nanogranular SiO2 film by RF sputtering the IZO target in an Ar ambient. Such TFTs exhibit a good performance at an ultralow operation voltage of 1.5 V, with a high field-effect mobility of 11.9 cm2/Vs, a small subthreshold swing of 94.5 mV/decade, and a large current on-off ratio of 7.14×106. Effects of protons in the SiO2-based solid state electrolyte films on the electrical performances of the IZO TFTs are also studied. It is observed that a big EDL capacitance can be obtained for SiO2 films dipped in pure water, as a result of the fact that there are more protons in such SiO2 films. Because of the migration of protons in SiO2 electrolytes, an anti-clockwise hysteresis is observed on the transfer curve. Moreover, a bigger hysteresis is observed at a higher gate voltage scan rate. Gate bias stressing stabilities are also studied the shifts in threshold voltage are observed to obey a stretched exponential function.

Charge Transfer across the Interface between LiNi0.5Mn1.5O4 High-Voltage Cathode Films and Solid Electrolyte Films

We have carried out a basic study on the charge transfer across the interface between LiNi0.5Mn1.5O4 (LNMO) thin-film cathodes and different solid electrolyte coatings, namely LiNbO3, ZrO2 and Li4Ti5O12. In contact to LNMO, the spinel material Li4Ti5O12 should act as a solid electrolyte, since it exhibits a very low electronic conductivity in the fully oxidized state. The thin films were prepared by means of sol-gel chemistry and spin-coating. The electrochemical and interfacial properties were studied by combining electrochemical impedance spectroscopy (EIS), time-of-flight secondary-ion mass spectrometry (ToF-SIMS) and cross-sectional SEM imaging. The results show that the LNMO / LiNbO3 interface combines a low charge transfer resistance with a high stability.

Lateral-coupling coplanar-gate oxide-based thin-film transistors on bare paper substrates

For conventional thin-film transistors (TFTs), bottom-gate or top-gate configuration is always adopted because the channel current is generally controlled by vertical capacitive coupling. In this article, depending on huge lateral electric-double-layer (EDL) capacitor induced by spatial movement of protons in phosphosilicate glass (PSG) solid electrolyte dielectrics, coplanar-gate indium–zinc–oxide (IZO)-TFTs based on the lateral capacitive coupling were fabricated on bare paper substrates. The PSG solid electrolyte films here were used at the same time as gate dielectrics and smooth buffer layers. These TFTs showed a low-voltage operation of only 1 V with a large field-effect mobility of 13.4 cm2 V−1·s, a high current on/off ratio of 6 × 106 and a small subthreshold swing of 75 mV/decade. Furthermore, with introducing another coplanar gate, AND logic operation was also demonstrated on the coplanar dual-gate TFTs. These simple lateral-coupling coplanar-gate IZO-TFTs on bare paper substrates are very promising for low-cost portable sensors and bio-electronics.

Advanced intermediate temperature sodium copper chloride battery

Sodium metal chloride batteries, also called as ZEBRA batteries, possess many merits such as low cost, high energy density and high safety, but their high operation temperature (270–350 °C) may cause several issues and limit their applications. Therefore, decreasing the operation temperature is of great importance in order to broaden their usage. Using a room temperature ionic liquid (RTIL) catholyte composed of sodium chloride buffered 1-ethyl-3-methylimidazolium chloride–aluminum chloride and a dense β″-aluminates solid electrolyte film with 500 micron thickness, we report an intermediate temperature sodium copper chloride battery which can be operated at only 150 °C, therefore alleviating the corrosion issues, improving the material compatibilities and reducing the operating complexities associated with the conventional ZEBRA batteries. The RTIL presents a high ionic conductivity (0.247 S cm−1) at 150 °C and a wide electrochemical window (−2.6 to 2.18 vs. Al3+/Al). With the discharge plateau at 2.64 V toward sodium and the specific capacity of 285 mAh g−1, this intermediate temperature battery exhibits an energy density (750 mWh g−1) comparable to the conventional ZEBRA batteries (728–785 mWh g−1) and superior to commercialized Li-ion batteries (550–680 mWh g−1), making it very attractive for renewable energy integration and other grid related applications.

Structural and dielectric studies of amorphous and semicrystalline polymers blend‐based nanocomposite electrolytes

ABSTRACTThe solid polymeric nanocomposite electrolyte (SPNE) films based on the blend of amorphous poly(methyl methacrylate) (PMMA) and semicrystalline poly(ethylene oxide) (PEO) (PMMA:PEO = 80:20 wt %) doped with lithium perchlorate (LiClO4) salt and montmorillonite (MMT) clay nanofiller were prepared by classical solution cast, ultrasonic assisted solution cast and ultrasonication along with microwave irradiated solution cast followed by melt‐pressing methods. The X‐ray diffraction study of these electrolytes revealed the amorphous behavior with intercalated MMT structures. The suppressed crystallinity of PEO in the blend electrolyte complexes confirmed the existence of single discrete PEO chains confined within the PMMA domains. The dielectric relaxation spectroscopy of these materials was performed over the frequency range 20 Hz to 1 MHz, at ambient temperature. The presence of a singular relaxation peak in the loss tangent and electric modulus spectra of these electrolytes confirms a coupled cooperative chain segmental dynamics of the blend polymer owing to their miscible amorphous morphology. The behavior of transient complexes formed between the polymers functional groups, lithium cations and the intercalated MMT nanoplatelets was explored. The ambient temperature ionic conductivity of these electrolytes depends on the structural dynamics and the sample preparation methods. It is revealed that the presence of PEO in the PMMA matrix mainly governs the structural, dielectric, and ionic properties of these SPNE films. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2015,132, 41311.

LiCoO2 Thin Film Deposition Using a Low-Temperature Electrochemical-Hydrothermal Route

The increasing miniaturization of electronic devices and the demand for stand-alone systems require adapted power sources in terms of dimensions and energy. All-solid-state microbatteries are an interesting solution for new applications (secured smart cards, medical implants, sensors, etc.). They are obtained by successive deposition of thin films of electrode active materials and solid electrolyte. However, these batteries have a rather low capacity (50-200 µAh/cm²) due to the difficulty to use electrodes thicker than 5µm (electronic conductivity, lithium diffusion and mechanical stress issues). Most of commercially available microbatteries use a LiCoO2 positive electrode due to its interesting properties: a 4V/Li+/Li nominal voltage, an excellent cycle life and a high electronic conductivity [1] . Thin films of LiCoO2 are mainly obtained by sputtering [2, 3] , followed by an annealing (500-700°C) necessary to obtain the electrochemically active phase of LiCoO2 (R-3m). This latter step then limits the possible substrates. Moreover the low deposition rate (10nm/mn) and the required equipments and facilities make this process quite costly.To circumvent these drawbacks, thin films of LiCoO2 were synthesized by a novel single-step route: the electrochemical-hydrothermal deposition. This technique combines the effects of the hydrothermal conditions (temperature and pressure) with a galvanostatic electrodeposition. Using ethanol as co-solvent in the aqueous media, we succeded in obtaining a pure and highly-crystalline LiCoO2 films, without any Co3O4 impurity. Moreover, the surface roughness is greatly decreased (fig.1) compared with films obtained in pure aqueous media. The obtained thickness can be increased up to 30µm, equal to a deposition rate of 200nm/mn. Galvanostatic cycling and linear sweep voltammetry experiments were carried out on these electrodes using CR2032 coin cells. The electrochemical properties of these films are very promising and clearly evidence the influence of each deposition parameter (temperature, current density, water/ethanol ratio, etc.) (fig2). [1] Reimers, J.N. and J.R. Dahn, Journal of the Electrochemical Society, 1992. 139(8): p. 2091-2097. [2] Wei, G., T.E. Haas, and R.B. Goldner, Solid State Ionics, 1992. 58(1-2): p. 115-122. [3] Wang, B., et al., Journal of the Electrochemical Society, 1996. 143(10): p. 3203-3213.

Low energy ion beam assisted deposition of controllable solid state electrolyte LiPON with increased mechanical properties and ionic conductivity

Lithium phosphorus oxynitride (LiPON) solid state amorphous film electrolytes were synthesized by ion beam assisted deposition (IBAD) using Li3PO4 target under nitrogen reactive plasma. IBAD presents an advantage of controllable nitrogen content of the films by adjusting N2 and Ar flow ratio. X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), nanoindenter, and profiler were employed to characterize LiPON films. Our results indicate that the film at N2 and Ar flow ratio of 1:8 showed the best surface morphology and mechanical properties. The highest N atomic percentage of 2.32% was also obtained at this synthesis circumstance, and the resultant LiPON film electrolyte showed higher ionic conductivity of 4.5 × 10−6 S/cm at room temperature, as well as the highest hardness of 6.8 GPa and the lowest compressive stress of 147.2 MPa. It is believed that as-prepared LiPON solid state electrolyte film optimized can effectively prevent delamination from electrodes, showing some promising application in thin film lithium ion batteries.

The Effects of Process Variation on the Parametric Model of the Static Impedance Behavior of Programmable Metallization Cell (PMC)

ABSTRACTAmong the new non-volatile memories gaining attention as a potential replacement for flash technology is the programmable metallization cell (PMC) that works by creating and dissolving a conductive bridge across a solid electrolyte film. This enables switching between a high resistance state (HRS) and a low resistance state (LRS). The dominant mechanism for resistance switching is field dependent ion transport in the film. In this work, we examine, through numerical simulation, the effects of process variation on the impedance characteristics of the PMC in both HRS and LRS, by changing key parameters of the device. These parameters include the material bandgap, affinity and permittivity of each device layer. Finally, we show which parameters have the greatest effects on the impedance behavior.

Li-rich anti-perovskite Li3OCl films with enhanced ionic conductivity.

Anti-perovskite solid electrolyte films were prepared by pulsed laser deposition, and their room-temperature ionic conductivity can be improved by more than an order of magnitude in comparison with its bulk counterpart. The cyclability of Li3OCl films in contact with lithium was evaluated using a Li/Li3OCl/Li symmetric cell, showing self-stabilization during cycling test.

Conductivity studies on (PVC/PEMA) solid polymer blend electrolyte films complexed with NaIO4

PVC—PEMA polymer blend based electrolyte films complexed with NaIO4 were prepared by solution—cast technique. The complexation of the blend with the salt was confirmed from XRD and SEM studies. DC conductivity was measured in the temperature range 303–398 K. The electrical conductivity increased with increasing dopant concentration. Which is attributed to the increase in amorphous nature of the complexes on dopining.. Transference number measurements were carried out to investigate the nature of charge transport. The discharge characteristics of the cells were studied under a constant load.

Electrical Characterization of YSZ Thin Films Using a Calibrated Platinum Micro-Electrode

A bulk platinum microelectrode calibration method, aiming at providing reliable measurements of the electrical properties of thin solid electrolyte films, is described. The method consists in the determination of the electrically active surface of an electrode of microscopic dimensions based on the confident measurement of the conductivity of a well know reference sample. The method is demonstrated to be efficient, reliable and reproducible in the case of yttria-stabilized zirconia films prepared by different techniques for films thicknesses ranging from 1.5 µm to 10 µm.

Studies on thin films of PVC-PMMA blend polymer electrolytes

Abstract Thin films of poly (vinyl chloride) (PVC)/poly (methyl methacrylate) (PMMA) blend polymers complexed with different concentrations of LiClO4 salt, containing ethylene carbonate (EC) as the plasticizer, were fabricated by the solution cast procedure. Ionic conductivity, thermal stability and X-ray diffraction (XRD) studies were undertaken. AC impedance measurements were done in the temperature range of 20–70°C. The highest ionic conductivity at room temperature was found to be 2.23×10-5 S cm-1 for the sample containing 15 wt% of LiClO4 salt. The XRD technique was used to investigate the structure and complex formation of solid polymer electrolytes. There was a decrease in degree of crystallinity. The amorphous nature of complexed solid polymer blend electrolyte films increased, due to the addition of LiClO4 salt. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) revealed the effect of salt on the thermal stability of the polymer electrolytes. It was found that these polymer electrolyte systems show stability up to about 280°C. It was also found that, with increased LiClO4 salt content in complexed polymer electrolyte systems, the degradation temperature decreased.