60 research outputs found

    Novel method of preparation of C/SnSnO2C/Sn-SnO_2 nanocomposite Li-ion anode material derived from plant polysaccharides

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    C/Sn - SnO 2 nanocomposite was obtained in one step pyrolysis and carbore duction process, providing formation of tin - based nanograins encapsulated in carbon buffer matrix derived from plan t polysaccharide (potato starch). Electrical conductivity of t he obtained material was carried out within temperature range - 20÷ 40 ̊ C. Cyclic voltammetry (CV) and charge - discharge tests were pe rformed in Li/Li + /(C/Sn - SnO 2 ) R2032 - type coin cells within 0.02 ÷ 1 .5 V potential range. Furthermore , electrochemical impedance spectroscopy (EIS) was used to characterize electrochemica l properties of the nanocomposite. The C/Sn - SnO 2 anode material provided at least 538 mAh g -1 at C/20 – rate and revealed good coulombic efficiency and capacity retention in charge - discharge cell tests

    Optimization of sulphur content in LiMn2O4ySyLiMn_2O_{4-y}S_y spinels as cathode materials for lithium-ion batteries

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    Sulphur doped lithium manganese spinels with a nominal composition of LiMn2O4-ySy (0≤y≤0.02) were synthesized by a modified sol-gel method followed by calcinations at 300 and 650 °C in air. The prepared materials were characterized in terms of physicochemical properties using X-ray powder diffraction (XRD), differential scanning calorimetry (DSC) and electrical conductivity studies (EC). Electrochemical characteristic of Li/Li+/LiMn2O4-ySy cells was examined by galvanostatic charge/discharge tests (CELL TEST), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). It was shown that small amount of sulphur in LiMn2O4 spinel enhances the structural integrity of the host material and increases the electrochemical performance

    A strategy to optimize the performance of bio-derived carbon aerogels by a structuring additive

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    In this work, we investigated the influence of gum arabic (GA) as a structuring additive, on the electrochemical behavior of bio-derived carbon aerogels (CAGs). Modified carbonaceous materials were prepared by the gelatinization process of potato starch (PS) with the addition of GA in various quantities, followed by the thermal treatment of the obtained gels in an inert gas atmosphere. The obtained anode materials were examined by X-ray diffraction (XRD), elemental analysis (EA), galvanostatic charge/discharge tests (GCDT), extensive cycling (LT-GCDT) and cyclic voltammetry (CV) methods. The highest electrochemical performance was achieved for carbon aerogel material, in which 1% w/w GA was added. The results showed that the proper composition of carbon precursor with a structuring promoter improves the rheological properties of starch gel and stabilizes the final aerogel structure affecting CAG functional properties

    Nitrogen-doped carbon aerogels derived from starch biomass with improved electrochemical properties for Li-ion batteries

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    Among all advanced anode materials, graphite is regarded as leading and still-unrivaled. However, in the modern world, graphite-based anodes cannot fully satisfy the customers because of its insufficient value of specific capacity. Other limitations are being nonrenewable, restricted natural graphite resources, or harsh conditions required for artificial graphite production. All things considered, many efforts have been made in the investigation of novel carbonaceous materials with desired properties produced from natural, renewable resources via facile, low-cost, and environmentally friendly methods. In this work, we obtained N-doped, starch-based carbon aerogels using melamine and N(2) pyrolysis as the source of nitrogen. The materials were characterized by X-ray powder diffraction, elemental analysis, X-ray photoelectron spectroscopy, galvanostatic charge–discharge tests, cyclic voltammetry, and electrochemical impedance spectroscopy. Depending on the doping method and the nitrogen amount, synthesized samples achieved different electrochemical behavior. N-doped, bioderived carbons exhibit far better electrochemical properties in comparison with pristine ones. Materials with the optimal amount of nitrogen (such as MCAGPS-N8.0%—carbon aerogel made from potato starch modified with melamine and CAGPS-N1.2%—carbon aerogel made from potato starch modified by N(2) pyrolysis) are also competitive to graphite, especially for high-performance battery applications. N-doping can enhance the efficiency of Li-ion cells mostly by inducing more defects in the carbon matrix, improving the binding ability of Li(+) and charge-transfer process

    Electrochemical properties and structure evolution of starch-based carbon nanomaterials as Li-ion anodes with regard to thermal treatment

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    The influence of the pyrolysis temperature on the structural, textural, and electrochemical properties of carbon aerogels obtained from potato, maize, and rice starches was analyzed. The carbonization of organic precursors, followed by gelatinization, exchange of solvent, and drying process, was carried out in an argon atmosphere at temperatures ranging from 600 °C to 1600 °C. The nanostructured carbons were characterized by X-ray powder diffraction (XRD) as well as N2-adsorption/desorption (N2-BET) methods. The electrochemical behavior of Li-ion cells based on the fabricated carbon anodes was investigated using the galvanostatic charge/discharge tests (GCDT) and electrochemical impedance spectroscopy (EIS). The results show that the thermal treatment stage has a crucial impact on the proper formation of the aerogel material’s porous structures and also on their working parameters as anode materials. The highest relative development of the external surface was obtained for the samples pyrolysed at 700 °C, which exhibited the best electrochemical characteristics (the highest specific capacities as well as the lowest charge transfer resistances)

    Multifunctional carbon aerogels derived by sol–gel process of natural polysaccharides of different botanical origin

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    In this manuscript, we describe the results of our recent studies on carbon aerogels derived from natural starches. A facile method for the fabrication of carbon aerogels is presented. Moreover, the complete analysis of the carbonization process of different starch aerogels (potato, maize, and rice) was performed using thermogravimetric studies combined with a detailed analysis of evolved decomposition products. The prepared carbon aerogels were studied in terms of their morphology and electrical properties to relate the origin of starch precursor with final properties of carbon materials. The obtained results confirmed the differences in carbon aerogels’ morphology, especially in materials’ specific surface areas, depending on the botanical origin of precursors. The electrical conductivity measurements suggest that carbon aerogels with the best electrical properties can be obtained from potato starch

    Materiały katodowe dla nowej generacji akumulatorów typu Li-ion

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    Od wielu lat kwestia uzyskania możliwie taniej energii do celów przemysło- wych i konsumpcyjnych nabiera coraz większej wagi. Wyczerpywanie się zaso- bów nieodnawialnych, jak również wymagania prawne w zakresie ochrony śro- dowiska zmuszają kraje o wysokim poziomie rozwoju gospodarczego do dywer- syfikacji źródeł wytwarzania i gromadzenia energii. Wśród szeregu urządzeń i układów do magazynowania energii, ze względu na obiecujące parametry użyt- kowe, do których należą: duża gęstość energii, wysokie napięcie pracy, niski współczynnik samorozładowania, dobra trwałość cykliczna oraz szeroki zakres temperatur pracy, na uwagę zasługują akumulatory Li-Ion. Obecnie jednym z największych wyzwań w konstrukcji systemów litowo-jonowych jest znale- zienie nowych rozwiązań materiałowych, które doprowadzą do zmniejszenia kosztów, poprawy parametrów pracy oraz bezpieczeństwa użytkowania ogniw

    Cathode materials for new generation lithium-Ion batteries

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    Od wielu lat kwestia uzyskania możliwie taniej energii do celów przemysłowych i konsumpcyjnych nabiera coraz większej wagi. Wyczerpywanie się zasobów nieodnawialnych, jak również wymagania prawne w zakresie ochrony środowiska zmuszają kraje o wysokim poziomie rozwoju gospodarczego do dywersyfikacji źródeł wytwarzania i gromadzenia energii. Wśród szeregu urządzeń i układów do magazynowania energii, ze względu na obiecujące parametry użytkowe, do których należą: duża gęstość energii, wysokie napięcie pracy, niski współczynnik samorozładowania, dobra trwałość cykliczna oraz szeroki zakres temperatur pracy, na uwagę zasługują akumulatory Li-Ion. Obecnie jednym z największych wyzwań w konstrukcji systemów litowo-jonowych jest znalezienie nowych rozwiązań materiałowych, które doprowadzą do zmniejszenia kosztów, poprawy parametrów pracy oraz bezpieczeństwa użytkowania ogniw.The concern about energy sources and comprehensive management of them has made rehargeable battery development into a growth area which has gained high rate for its research activities. Out of all the possible rechargeable systems, the lithiumion batteries appear to be one of the most dominant and effective technologies in the field of energy storage. They offer high voltage, high energy density, flexible and lightweight design, improved efficiency and longer cycle life than comparable battery technologies. These basic benefits underline the attractiveness of the solution and indicate the application prospects in the field of the portable, entertainment, computing and telecommunication equipment required by today's informationrich, mobile society as well as electric vehicles or renewable energy storage systems. Despite the impressive growth in sales of batteries worldwide, we are still looking for new materials to reduce costs, improve performance and safety of batteries
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