Fundamental Study of Engineered Nanocrystalline and Amorphous Silicon Based High Capacity, Reversible and Stable Anodes for Lithium-Ion Batteries

Commercial lithium-ion battery (LIB) systems at present employ graphite as the anode having a theoretical capacity of 372 mAh/g. However, for hybrid electric vehicles and electrical grid energy storage, batteries with much higher capacity and cycle life are needed. There is hence a critical need to explore alternative higher capacity alternative systems. Silicon, with a theoretical capacity of 4200 mAh/g is widely considered a promising alternative candidate anode to graphite. However, Si undergoes colossal volume expansion (>300%) during lithium alloying and de-alloying. This leads to pulverization resulting in loss of electrical contact of Si with the current collector thereby causing rapid decrease in capacity and consequent failure. It has been demonstrated that nanostructured (nc-Si) and amorphous (a-Si) forms of Si and Si based nanocomposites provide mechanical integrity preventing pulverization due to the reduced number density of atoms within a nano-sized grain and the ‘free volume’ effects in amorphous Si resulting in better capacity retention and cycle life. In this dissertation, the following simple and cost effective approaches for generating nanostructured composites of silicon are discussed: (1) Si nanoparticles of high specific surface area by high energy mechanical milling (HEMM), (2) Amorphous silicon (a-Si) films by electrodeposition, (3) Heterostructures of vertically aligned carbon nanotubes (VACNTs) and Si by chemical vapor deposition (CVD), and (4) low cost template based high throughput synthesis of hollow silicon nanotubes (h-SiNTs). All of the above amorphous and nanocrystalline Si based composites were thoroughly investigated using material and electrochemical characterizations and accordingly, a structure-property relationship was established. Among the aforementioned structures, the electrodeposited a-Si films exhibited excellent cyclability (0.016% loss per cycle), while CNT/Si heterostructures showed a very low first cycle irreversible loss of only 10%. The hollow silicon nanotubes exhibited a reasonable first cycle irreversible loss (25%) but exhibited extraordinary cycling stability with a low capacity fade rate of ~0.06%loss/cycle at the end of 400 cycles. These amorphous and nanocrystalline based silicon anodes prepared by cost effective methods, due to their superior electrochemical properties, show considerable potential to replace the current graphite based anodes for the next generation of high energy density Li-ion batteries

Isolation And Characterization Of Microorganisms From Pesticide Treated Soils Of Different Regions Of Telangana

This investigation is carried out to identify the microorganisms for the pesticide treated soil samples collected from different places of Warangal District, Telangana. The identification was based on morphological, physiological and biochemical. Randomly five samples from one village haven selected. The type and amount of pesticide used by the farmers have been noted. With reference to the results of morphological, physiological and biochemical, we identified 10 bacterial genus namely, Pseudomonas, Bacillus, Streptomyces, Rhizobium, Klebsiella, Staphylococcus, Streptococcus, Azatobacter Azospirillum, Actinomycetes and 06 fungal genus namely,  Aspergillus, Penicillium, Trichoderma, Fusarium, Rhizopus and Vesicular Arbuscular Mycorrhiza have been predominantly identified from all the samples collected

Biodegradation Of Synthetic Compounds By The Microorganisms Isolated From Different Regeions Of Telangana

The extensive use of synthetic compounds, including pesticides, has raised concerns about their environmental impact and potential risks to human health. Microbial biodegradation has emerged as a promising eco-friendly approach to mitigate the accumulation of these compounds in the environment. In this study, we investigated the biodegradation potential of found microorganisms isolated from pesticidetreated soils in different regions of Telangana State. 50 Soil samples were collected from agricultural areas in diverse regions, known for their significant pesticide usage. Enrichment cultures were prepared using these soil samples to isolate predominantly found 10 bacterial and 5 fungal genus capable of utilizing synthetic compounds as a carbon and energy source. The isolated microbial strains were characterized by morphological, physiological, and biochemical characteristics. Subsequently, the biodegradation potential of the isolated microorganisms was assessed through laboratory-scale degradation experiments. Commonly used pesticides were selected as model substrates for degradation studies. The degradation efficiency of the microorganisms was evaluated at different incubation periods (05, 10 and 15 days) to understand their ability to break down these synthetic compounds. The results demonstrated that the degradation of pesticides by bacteria and fungi was found significant after 15th day of incubation. The degradation of tested pesticides was initiated from the 5th day. At the end of 10th day there is an exponential degradation percentage. By 15th day the degradation percentage was approximately 1fold compared to 10th day degradation percentage. This investigation emphasizes the significance of harnessing the potential of bacteria and fungi to mitigate the environmental burden of synthetic compounds. The findings hold practical implications for developing eco-friendly and region-specific bioremediation strategies to combat pollution caused by synthetic compounds and promote environmental sustainability in the agricultural secto

Pulsed Current Electrodeposition of Silicon Thin Films Anodes for Lithium Ion Battery Applications

Electrodeposition of amorphous silicon thin films on Cu substrate from organic ionic electrolyte using pulsed electrodeposition conditions has been studied. Scanning electron microscopy analysis shows a drastic change in the morphology of these electrodeposited silicon thin films at different frequencies of 0, 500, 1000, and 5000 Hz studied due to the change in nucleation and the growth mechanisms. These electrodeposited films, when tested in a lithium ion battery configuration, showed improvement in stability and performance with an increase in pulse current frequency during deposition. XPS analysis showed variation in the content of Si and oxygen with the change in frequency of deposition and with the change in depth of these thin films. The presence of oxygen largely due to electrolyte decomposition during Si electrodeposition and the structural instability of these films during the first discharge–charge cycle are the primary reasons contributing to the first cycle irreversible (FIR) loss observed in the pulse electrodeposited Si–O–C thin films. Nevertheless, the silicon thin films electrodeposited at a pulse current frequency of 5000 Hz show a stable capacity of ~805 mAh·g−1 with a fade in capacity of ~0.056% capacity loss per cycle (a total loss of capacity ~246 mAh·g−1) at the end of 500 cycles

A mini-review on the development of Si-based thin film anodes for Li-ion batteries

This review provides a summary of the progress in research on various Si-based thin films as anode materials for lithium-ion batteries. The lithiation mechanism models, different types of materials from pure monolithic Si thin film to Si-based three-dimensional structured composite thin films, the effect of liquid and solid-state electrolytes on the performance of Si were considered and various available preparation techniques were discussed. A table summarizing important information on such systems including the thin film features, preparation methods and conditions, electrochemical test conditions and obtained results in order to elucidate the approaches used to prepare a stable thin film anode with high capacity and long cycle life is provided. We believe that this review will help the researchers to find some answers and induce some new ideas

Покарання за злочини проти євреїв та за злочини євреїв у Великому князівстві Литовському

Єпур М. В. Покарання за злочини проти євреїв та за злочини євреїв у Великому князівстві Литовському / М. В. Єпур // Актуальні проблеми політики : зб. наук. пр. / редкол. : С. В. Ківалов (голов. ред.), Л. І. Кормич (заст. голов. ред.), Ю. П. Аленін [та ін.] ; МОНмолодьспорт України, НУ ОЮА. - Одеса : Фенікс, 2010. - Вип. 40. - С. 473-479.The institute of punishment, which operated in Jewish communities of the Grand Duchy of Lithuania in XIV – XVI centuries, is probed in the article. It is underlined that jewish succeeded to save the autonomy of the legal proceeding which was conducted on the basis of the Jewish legislation. The types of crimes and punishments which was used to jewish in accordance with this legislation are characterized. The state acts of the Grand Duchy of Lithuania, directed on defence right privileges of the Jewish population

Pulsed Current Electrodeposition of Silicon Thin Films Anodes for Lithium Ion Battery Applications

Electrodeposition of amorphous silicon thin films on Cu substrate from organic ionic electrolyte using pulsed electrodeposition conditions has been studied. Scanning electron microscopy analysis shows a drastic change in the morphology of these electrodeposited silicon thin films at different frequencies of 0, 500, 1000, and 5000 Hz studied due to the change in nucleation and the growth mechanisms. These electrodeposited films, when tested in a lithium ion battery configuration, showed improvement in stability and performance with an increase in pulse current frequency during deposition. XPS analysis showed variation in the content of Si and oxygen with the change in frequency of deposition and with the change in depth of these thin films. The presence of oxygen largely due to electrolyte decomposition during Si electrodeposition and the structural instability of these films during the first discharge–charge cycle are the primary reasons contributing to the first cycle irreversible (FIR) loss observed in the pulse electrodeposited Si–O–C thin films. Nevertheless, the silicon thin films electrodeposited at a pulse current frequency of 5000 Hz show a stable capacity of ~805 mAh·g−1 with a fade in capacity of ~0.056% capacity loss per cycle (a total loss of capacity ~246 mAh·g−1) at the end of 500 cycles