Influence of polymer binder structure on the properties of the graphite anode for lithium-ion batteries

This paper discusses the impact of the structure and properties of three different polymer binders: polyvinylidene fluoride, sodium carboxymethyl cellulose and polyvinyl alcohol, on the electrochemical properties of spherical graphite anodes for Li-ion batteries. Electrochemical tests indicate that the nature of polyvinylidene fluoride contributes in decreasing the cycle life of graphite electrodes in contrast to effective water-based binders. This study demonstrates the possibility of manufacturing graphite-based electrode for Li-ion batteries that cycle longer and use water in the processing, instead of hazardous organic solvents like N-methylpyrrolidone, thereby improving performance, reducing cost and protecting the environment

Platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane Complex as a Pt Source for Pt/SnO2 Catalyst

This paper presents new preparation method of Pt/SnO2, an important catalytic system. Besides of its application as a heterogenic industrial catalyst, it is also used as a catalyst in electrochemical processes, especially in fuel cells. Platinum is commonly used as an anode catalyst in low temperature fuel cells, fuelled with alcohols of low molecular weight such as methanol. Platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex was used as a precursor of metallic phase. The aim of the research was to obtain a highly active in electrochemical system Pt/SnO2 catalyst with low metal load. Considering small size of Pt crystallites, it should result in high activity of Pt/SnO2 system. The presented method of SnO2 synthesis allows for obtaining support consisting of nanoparticles. The effect of the thermal treatment on activity of Pt/SnO2 gel was demonstrated. The system properties were investigated using TEM, FTIR (ATR), and XRD techniques to describe its thermal structural evolution. The results showed two electrocatalytical activity peaks for drying at a temperature of 430 K and above 650 K

One-pot method of synthesis and supercritical carbon dioxide drying of PVdF-HFP composite membranes

This paper describes one-pot method of the synthesis and properties of composite polymer gel electrolytes based on poly(vinylidenefluoride-co-hexafluoropropylene) (PVdF-HFP). As the precursor of the inorganic filler tetraethyl orthosilicate (TEOS) and titanium tetra-n-butoxide (Ti(OC4H9)4) were used. The drying of membranes with fillers was carried out with supercritical CO2. The membranes and gel electrolytes have been examined structurally and electrochemically, showing favorable properties in terms of electrolyte uptake and electrochemical characteristics in Li-ion cells

NEW METHOD OF OBTAINING GELATINE-SiO₂ COMPOSITE SYSTEMS USING 3-GLYCIDOXYPROPYLTRIMETHOXYSILANE AND 3-CHLOROPROPYLTRIMETHOXYSILANE

Composite materials based on biopolymers are an attractive alternative to conventional composites because of their high biocompatibility, biodegradability and unique functional characteristics. The method developed for the synthesis of material using glycidoxypropyltrimethoxysilane and chloropropyltrimethoxysilane is based on sol-gel processes making possible enhanced control over the final properties of the composite, such as water absorption and the hydrophobic or hydrophilic properties. Thermal studies of the composite show significant complexity of the formation process of the composite, and the possibility of the controlled carbonization into ceramic material

NEW ROUTE TO MESOPOROUS SILICA ‎VIA A SILSESQUIOXANE PRECURSOR

The effect of the addition of octakis(tetramethylammonium)-t8-silsesquioxane (octaanion) on the modification of the porous structure of the silica gel obtained by the sol-gel method catalysed by acetic acid was studied. The obtained silica gel was characterised by the low-temperature nitrogen adsorption/desorption method (BET), powder diffraction (XRD), thermogravimetry (TG) and microscopic observations (TEM). The octaanion was found to act as a textural promoter, as evidenced by almost a 25% increase in the surface area of the obtained silica. As a result of the stabilisation in the porous structure of the silica gel, the tetramethylammonium groups of the octaanion show higher thermal stability than the groups present in the octaanion structure or those introduced in the form of tetramethylammonium hydroxide. Tetramethylammonium ions were proved to show increased thermal resistance, which is related to the porous properties of the SiO₂ matrix