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Composite solid polymer electrolytes (CSPEs) are promising candidates for replacing potentially hazardous organic liquid electrolytes used in Li ion batteries (LIBs). CSPEs are easy to process, have the ability to form films, and make better interfacial contact. However, their poor mechanical strength, low ionic conductivity, and long cycling stability limit their practical applications. Here, we demonstrate the fabrication of a cost-effective, flexible, self-standing, and highly stable CSPE using poly(propylene carbonate) (PPC) as the host matrix and highly mesoporous silica nanoparticles (MSNs) as the filler. The fabricated CSPE had a high ionic conductivity of approximately 8.5 × 10−4 S cm−1 at 60°C, electrochemical potential stability up to approximately 4.8 V vs. Li/Li+, an ultra-high lithium transference number of approximately 0.86, impressive stability over 1000 h of Li stripping/plating, and an excellent electrode compatibility. With cyclability over 200 cycles and a negligible overpotential, the Li/CSPE/LFP cell delivered a reversible capacity of 171 and 103 mAh g−1 at 0.1 C and 1 C, respectively, with a good rate capability up to 5 C. The interaction of Li+ with PPC and the MSNs is demonstrated by solid-state magic angle spinning nuclear magnetic resonance (MAS-NMR) and X-ray photoelectron spectroscopy (XPS) studies. The enhanced physico-electrochemical properties of the CSPE were attributed to the large MSNs-related surface area, which enables firm interaction with the PPC matrix and provides a less-tortuous polymer-ceramic phase for fast lithium ion transportation. The proposed MSNs-reinforced CSPE thus opens new possibilities for the fabrication and engineering of solid-state batteries.

In this article, we report the effect of using nanoparticles for LiMn2O4 cathode materials in flexible batteries with organic–inorganic hybrid electrolytes. LiMn2O4 nanoparticles for the cathode are prepared by pyro-synthesis. Electrochemical measurement indicated the discharge capacities were 118.41 and 138.12 mA h g−1 and the coulombic efficiencies were 91.50% and 97.28% for the micro- and nano-LMO materials, respectively. This is attributed to the nano-LiMn2O4 material having particle sizes in the nanoscale dimension, and shorter diffusion paths combined with a large contact area at the electrode/electrolyte interface. Furthermore, the pouch-type cells demonstrated similar properties, with initial discharge capacities of 85.63 and 99.96 mA h g−1 and coulomb efficiencies of 79.27% and 90.27% for the micro- and nano-LMO cells, respectively. Nanoparticles allow Li+ ions to de-intercalate and intercalate very easily because of the very short lithium diffusion distance.

The PEO/LLZO solid composite electrolyte with high ionic conductivity and low interfacial resistance was prepared by solution casting method. The electrochemical properties such as lithium ion conductivity, lithium ion transference number, electrochemical stability and compatability with lithium metal anode of PEO/LLZO solid composite electrolyte were investigated. The results showed that the addition of LLZO could effectively improve the ionic conductivity, electrochemical stability window, transference number, and compatibility with lithium metal of composite electrolytes. The LLZO 45% content of the PEO/LLZO solid composite electrolyte showed the lowest activation energy and the electrochemical stability at 4.75V (vs Li/Li+). In addition, when the thickness of the PEO/LLZO solid composite electrolyte was 130 μm or more, The behavior of Li+ plating/stripping on lithium symmetric cell was greatly enhanced. The NCM622/Li solid-state lithium ion battery assembled with the PEO/LLZO solid composite electrolytes had good cycling performance. At current rate of 0.5C, the discharge specific capacity remained about 148mAh/g after 100cycles at 60℃.

The high price of metal-based electrolyte is delaying commercialization of the metal-based redox flow battery (RFB). Instead, the alkaline-based organic redox flow battery (AORFB) using synthetic active compounds, e.g., alloxazine 7/8-carboxylic acid (ACA), is attracting attention as a promising alternative. However, the working principle of the AORFBs is still unclear. This study aims to theoretically elucidate the working mechanism of the ACA-based AORFB by, for the first time, taking a computational approach. First, experimentally determined kinetic parameters were used to construct a transient, multi-dimensional model. Then, the developed computational model of the AORFB was used to investigate the effects of operating conditions. The results showed that the negative activation overpotential is less than 50.0% of positive side. The ionic conductivities of negative and positive electrolyte were estimated in a range of (51.2 to 69.2) S m−1 and (45.7 to 53.2) S m−1, respectively. Further, at low positive flowrate (15 mL min−1), the [Fe(CN)6]4− concentration decreased from (250 to 16.39) mol m−3, which caused a large potential loss. Finally, it was found that diffusion and electro-osmosis drag dominated water permeation through the membrane in the AORFB.

Solid electrolytes are a potential candidate for mitigating the safety issues associated with organic liquid-electrolyte-based conventional Lithium-Ion Batteries (LIBs). The film-forming ability, cost-effective fabrication, and superior interfacial contact of solid polymer electrolytes make them particularly appealing for application in all-solid-state LIBs (ASSLIBs). However, their practical applications are limited owing to their low lithium-ion conductivity and inadequate mechanical strength. In this study, we fabricated a highly flexible, soft, self-standing, and stable composite solid polymer electrolyte (CSPE) using poly(propylene carbonate) (PPC) as the main matrix and Na-superionic-conductor-type Li1.5Al0.5Ge1.5(PO4)3 (LAGP) as the active inorganic filler. The fabricated CSPE exhibited an attractive ionic conductivity of ∼0.56 mS∙cm−1, a wide electrochemical potential stability of ∼5 V vs. Li/Li+, a high lithium-ion transference number of ∼0.77, outstanding stability up to 1000 cycles of lithium plating/stripping, and better compatibility with lithium metal. In addition to these outstanding properties, the Li/CSPE/LiFePO4 (Li/CSPE/LFP) cell exhibited an impressive discharge capacity of 151 mAh∙g−1 at 0.1 C. Furthermore, at a rate of 1 C, the Li/CSPE/LFP cell delivered an initial discharge capacity of 96 mAh∙g−1, with a capacity retention of 63% over 1000 cycles. The interaction of lithium ions with the PPC was confirmed based on solid-state MAS NMR and XPS. The enhanced electrochemical performance of the CSPE is ascribed to the interaction of the LAGP filler with the PPC matrix, which forms a good polymer-inorganic interface, enabling the rapid lithium-ion transport. The proposed LAGP-reinforced CSPE presents new opportunities for the fabrication and engineering of ASSLIBs.

Li7La3Zr2O12 powders with cubic phase and high ionic conductivity were synthesized using co-precipitation process, in which the mixture precursors of La–Zr–(OH)x and Li source were calcined and sintered at different conditions. XRD analysis showed that cubic phase of garnet-type LLZO powder is formed as calcined at 700 and 800 °C, respectively. However, tetragonal phase is formed at above 900 °C. As these samples were sintered in the form of pellets at 1200 °C, LLZO powder calcined at 700 °C showed excellent ionic conductivity of 3.2 × 10−4 S cm−1 at 25 °C, indicating cubic structure of LLZO single phase and high relative density of above 90% that is different with LLZO powder calcined at 900 °C.

Electro-spun nanofiber web is highly attractive as a separator for lithium ion batteries because of its high electrical properties. In moving toward wider battery applications of the nanofiber separators, a deeper understanding on the structure and property relationship is highly meaningful. In this regard, we prepared electro-spun poly(vinylidene fluoride) (PVdF) webs with various thicknesses (10.5~100 µm) and investigated their structures and electrochemical performances. As the thickness of the web is decreased, a decrease of porosity and an increase of pore size are resulted in. For the 10.5 µm-thick separator, a minor short-circuit was detected, stressing the importance of reducing pore-size on prevention of short-circuit. However, above the thickness of 21 µm, well-connected, submicron-sized pores are generated, and, with lowering the separator thickness, discharge capacity and rate capability are enhanced owing to the lowered area-specific resistance.

With an aim to enhance the thermal stability and electrolyte wetting of a polyethylene porous separator, an Al2O3 nano-powder layer and an electro-spun PVdF nanofiber layer were successively formed on both sides of the polyethylene separator. The Al2O3 layer provides excellent thermal stability as indicated by thermal shrinkage of only 7.8 % in area at 180 °C and absence of a meltdown up to 200 °C. The electrolyte uptake of the multilayer separator was increased with the thickness of the nanofiber layer. As a result, discharge capacity, rate capability, and cycle life of the lithium ion batteries employing the PVdF nanofiber layers were improved, overcompensating for a loss of performance caused by the Al2O3 layer. Therefore, the multilayer approach is highly effective in improving both the performance and safety of lithium ion batteries.

Electrospun polyvinylidene fluoride (PVDF) nanofiber membranes have 3-dementional (3-D) open pore channel and hence have excellent application potential in Western blot. In this study we have modified electrospun PVDF nanofiber membrane by argon (Ar) plasma treatment to improve the surface hydrophilic and detection sensitivity. The results showed that the detection sensitivity of the Ar plasma-treated PVDF nanofiber membrane increased with increasing plasma treatment time without the need for a methanol pre-wet step. This suggests that the Ar plasma treated PVDF nanofiber membrane can be useful in Western blot with high sensitivity and without methanol pre-wet step.

The CO2 gas sensor, based on the principle of electro-chemistry, was fabricated using the solid-electrolyte Li3PO4 film formed by a thermal evaporator and its sensing performances were studied. Thermal evaporated film was prepared with power of 10A, a working pressure of 10−6 mTorr and thickness of 1.2 µm. Then, it was annealed at 800 °C for 2h in air. Li2TiO3+TiO2 and Li2CO3 film were prepared using a screen printing method as the reference and the sensing electrode, respectively. Li3PO4 film showed a much denser structure than bulk-type Li3PO4 in SEM images. The response and recovery characteristics were very good at the higher CO2 concentration and its value was 280 mV and changed to 260 mV in the higher CO2 environment. It was also observed that the sensitivity decreased by 98 % when the CO2 concentration increased from 250 ppm to 5000 ppm. Response time and recovery time were measured to be 5 s and 7 s, respectively. These results showed enough potential for developing a CO2 gas sensor using Li3PO4 film instead of the bulk-type.

Intrinsic and phosphorus-doped hydrogenated microcrystalline silicon (microc-Si:H) films were prepared using inductively coupled plasma chemical vapor deposition (ICP-CVD) method. Structural, electrical and optical properties of these films were studied as a function of silane concentration, ICP source power and PH3/SiH4 gas ratio. Characterization of these films from Raman spectroscopy and X-ray diffraction revealed that the conductive film exists in microcrystalline phase embedded in an amorphous network. The condition of electrical properties (sigma(d): approximately 10(-7) S/cm, sigma(ph): approximately 10(-4) S/cm) and activation energy (0.55 eV), satisfied with properties of intrinsic microc-Si:H, was obtained at 1200 W of ICP power and 2% of silane concentration, respectively. At PH3/SiH4 gas ratio of 0.09%, dark conductivity has a maximum value of approximately 18.5 S/cm and optical bandgap also a maximum value of approximately 2.39 eV. The deposition rate was not satisfactory (4.9 angstroms/s) at same condition.

An electrolyte based on a mixture of tetra(ethylene glycol) dimethyl ether (TEGDME) and 1,3-dioxolane (DOXL) is studied for a use in lithium–sulfur battery. The maximum ionic conductivity is found at the intermediate mixing ratio of TEGDME:DOXL ¼ 30:70, because TEGDME readily solvates LiCF3SO3 and DOXL effectively reduces the viscosity of the electrolyte medium. The lithium–sulfur battery based on the binary electrolyte shows two discernable voltage plateaux at around 2.4 and 2.1 V, which correspond to the formation of soluble polysulfides and of solid reduction products, respectively. The UV spectral analysis for TEGDME-based and DOXL-based electrolytes suggests that the shorter polysulfide is favourably formed for DOXL-based electrolyte in the upper voltage plateau at around 2.4 V. The lower voltage plateau at around 2.1 V is highly dependent on the TEGDME:DOXL ratio. The sulfur utilization in the lower voltage plateau region can be correlated with the viscosity of the electrolyte, but with the ionic conductivity. The low polysulfide diffusion for the electrolyte with high viscosity causes significant passivation at the surface of the positive electrode and results in low sulfur utilization. # 2002 Elsevier Science B.V. All rights reserved.

Al-doped ZnO (AZO) films were deposited onto glass substrates by RF magnetron sputtering for solar cell applications. The effects of the Al2O3 doping concentration on the structural, electrical, and optical properties of the AZO films were investigated. As the Al2O3 doping concentration was increased to 4.0 wt %, X-ray diffraction (XRD) showed a deterioration in the (002) peak intensity and a shift towards a higher angle. The best electrical properties (ρ= 9.8×10-4 Ω cm, µH = 22 cm2 V-1 s-1, and ne = 2.89×1020 cm-3) were obtained in the AZO sample containing 2 wt % Al2O3. Optical transmission >83% in the visible range was also observed and the optical bandgap was increased to 3.63 eV at an Al2O3 concentration of 4 wt %. For photoluminescence (PL) spectra, one UV emission peak at approximately 3.2 eV and a broad peak in the visible range from 2.3 to 2.7 eV were observed at Al2O3 doping concentrations ranging from 0–2.0 wt %. Blue emission at 2.67 eV, which indicates a non-stoichiometric structure, was only observed in the 4 wt % doped AZO films.

In a previous study, an electrospun polyvinylidene fluoride (PVDF) nanofiber membrane was developed for Western blotting. The membrane exhibited high sensitivity and high binding capacity for the detection of protein bands that was unlike that observed for conventional, microphase separation-based porous PVDF membranes. Nevertheless, the PVDF nanofiber membrane is quite expensive. The objective of this study was to develop an economical Western blot membrane using a hybrid electrospun PVDF nanofiber and polyethylene terephthalate (PET) sheet. The results showed that the detection sensitivity of the 4 gram per square meter (gsm) membrane was similar to those of the electrospun PVDF nanofiber membrane only, and the 7 gsm PVDF nanofiber membranes on a PET sheet and the electrospun PVDF nanofiber membrane. This means the protein detection sensitivity is not proportional to the thickness of the PVDF nanofiber membrane. The 4 gsm PVDF nanofiber membrane on a PET sheet can be used to detect proteins with high sensitivity and economic efficiency.

The removal of free fatty acid (FFA) in waste frying oil by esterification with methanol was conducted using various zeolite catalysts. The ZSM-5 (MFI), mordenite (MOR), faujasite (FAU), beta (BEA) zeolites, and silicalite were employed with different Si/Al molar ratio in the reaction. The effects of acidic properties and pore structure of the zeolite catalysts were discussed relating to the conversion of the FFA. The MFI zeolite induced an improvement of the removal efficiency of FFA by cracking to the FFA in its pore structure due to its narrow pore mouth. The catalytic activity for FFA removal was lowered with decreasing of acid strength of the zeolites. The strong acid sites of zeolites induced the high conversion of FFA comparatively. The acid strength and pore structure of acidic zeolites affected the catalytic activity in FFA removal.

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The structure and the room temperature performances of sulfur cathodes composed of sulfur, carbon, and polyethylene oxide) (PEO) binder were studied with varying preparation method and binder content. Two different methods, ball mixing and mechanical stirring, were employed for preparation of slurry to obtain morphologically different cathodes. The cathodes prepared with mechanical stirring (SC cathodes) revealed more porous structure than those with ball mixing (BC cathodes). Scanning electron microscopy observations showed that sulfur particles were covered with dense and thick PEO film in the BC cathodes, whereas sulfur particles were bonded with porous PEO film in the SC cathodes. The SC-based cells exhibited much higher discharge capacity yielding 75% of sulfur utilization than the BC-based cells. The difference of discharge behaviors with different mixing methods indicates that the porosity of the cathode and the morphology of PEO binder are highly important factors for favorable electrochemical performance of lithium sulfur batteries. The cycle life of the SC-based cell was improved with the increase of binder content and with the roll pressing due to the increase of adhesiveness and cohesiveness of the sulfur cathode.