Marie Sedlaříková

Gel polymer electrolytes based on PMMA

New polymer gels (based on PMMA/PC) containing Li, Na, Mg, and Zn perchlorates were prepared. The conductivity of gels containing cations of smaller ionic radii (Li and Mg) is lower than that of the others.

Gel polymer electrolytes based on PMMA III. PMMA gels containing cadmium

Gel polymer electrolyte containing cadmium perchlorate was prepared by polymerisation of methylmethacrylate with a solution containing Cd perchlorate in propylene carbonate (PC). Electric conductivity, fundamental electrochemical properties and Cd electrodeposition were investigated. The deposition of Cd was fairly homogenous.

Study of electrochemical properties and thermal stability of the high-voltage spinel cathode material for lithium-ion accumulators

This article deals with the properties of high-voltage cathode material LiNi0.5Mn1.5O4 synthesised by a solid-state reactions method. The sample—LiNi0.5Mn1.5O4—was synthesised by two steps of annealing process. A number of electrochemical and physical methods were used to analyse the samples. The obtained LiNi0.5Mn1.5O4 powder was characterised by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and galvanostatic charge/discharge measurements at different loads and high temperature in lithium-ion cells with metal lithium as a counter electrode. All these analyses were used for confirmation of the structure of the material LiNi0.5Mn1.5O4 and for investigating its electrochemical properties. A special analysis was used for this paper to understand and confirm the function of this type of material. It is called electron paramagnetic resonance (EPR) spectroscopy, which is used in the field of lithium-ion batteries and also which is not common. This analysis is typically used to analyse free radicals. It is possible to study changes of valence in cathode materials during charging and confirming the valence change of Mn from Mn3+ to Mn4+ and of Ni from Ni2+ to Ni3+ and then to Ni4+ with EPR analysis. Thermogravimetric (TG) analysis of stability of the material LiNi0.5Mn1.5O4 with in situ observation of structural changes by SEM was used as the last analysis.

The influence of used precursors on the properties of high-voltage cathode materials

This article deals with the influence of precursors used in the high-voltage cathode material LiNi0.5Mn1.5O4 based on the LiMn2O4 material on its properties. Precursors with various sizes of particles were used for making the cathode material. Consequently, its influence on the stability during cycling, change of load, and the influence of higher temperatures during cycling were investigated. Produced materials were further analyzed to discover the influence of the change of the used precursor on the structure of the cathode material. The structure of the material deposited on Al foil was investigated by atomic force microscopy (AFM), and also X-ray photoelectron spectroscopy (XPS) analysis was performed. The materials were then observed by SEM and analyzed by the EDAX method. The results show that smaller particle size enhances the properties of cathode material both in the stability during cycling and higher capacity and also the potential under higher load.

Incorporation of Multielement Doping into LDH Structure of Alpha Nickel Hydroxide

Reffered-to work was aimed at clarifying of the reasons for its transformation tendency with the aim of finding a proper inhibition method. Based on our former experience with an individual-elements doping, simultaneous incorporation of the selected elements into brucite type lattice of nickel hydroxide appears to be suitable solution for fulfilment of the purpose.

Insights on electrochemical properties of gel polymer electrolytes based on methylmethacrylate

This paper explains some properties of gel polymer electrolytes, which are mostly used in lithium ion batteries. An emphasis is laid on the internal structure and its influence on the mobility of ions in the substance. The ions are solvated and located randomly in the liquid base of the gel, and their movement is predominantly determined by the Stokes law for liquid electrolytes. Polymethylmethacrylate gel is used as a model substance here. This report is based on the experience of the authors and their associates.

Lithiated graphite materials for negative electrodes of lithium-ion batteries

For the first time an attempt was made to eliminate problems of irreversible charging in the first cycle when a new lithium-ion battery is set to work. The research work was based on an artificial lithiation of the carbonaceous anode via three lithiation techniques: the direct electrochemical method, lithiation using FeCl3 as mediator, and via a direct contact with metallic Li. The cycling ability and specific capacity were the criteria of suitability, the contact with metal lithium was found to be the most efficient one. The battery grade carbon and/or expanded graphite were used as anode materials.

Electrochromic Glazings for Window Applications

Electrochromic materials have found practical applications in special devices such as: - systems with controlled transmission (surfaces with regulated radiation-electrochromic glazings), - systems with controlled reflection (electrochromic mirrors with regulated solar reflectance), and - systems with change of color contrast (special electrochromic information displays). This paper deals with electrochromic devices with a controlled transmission. Electrochromic glazings can be described as devices based on electrochromic materials that operate as reversible switching solar control shutters. These special glasses have found application not only for window glazing in hot climatic conditions but they are also recommended for buildings with large glazed shells where overheating and glare effect represent serious problem for daily service and operation.

International meeting on modern batteries ABA-10

Tenth annual meeting “Advanced Batteries and Accumulators ABA-10” was arranged in Brno in summer 2009