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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Room Temperature Molten Liquids Based On Amides : Electrolytes For Rechargeable Batteries, Capacitors And Medium For Nanostructures

Venkata Narayanan, N S 08 1900 (has links)
Room temperature molten liquids are proposed to be good alternates for volatile and harmful organic compounds. They are useful in varied areas of applications ranging from synthesis, catalysis to energy storage molten electrolytes have certain unique characteristics such as low vapour pressure, reasonably high ionic conductivity, high thermal stability and wide electrochemical window. These molten liquids can be classified in to two types depending on the nature of the species present in the liquids. One, those liquids consists only of ions (e.g) conventional imidazolium based ionic liquids and other that consists of ions and solvents (e g) acetamide eutectics. Acetamide and its eutectics from room temperature molten solvents that is unique with interesting physicochemical properties. The solvent properties of molten acetamide are similar to water, with high dielectric consist of 60 at 353 k. its acid – base properties are also similar to water, and it can solublise variety of organic and inorganic compounds as well. in the present studies room temperature molten liquids consisting of acetamide as one of the components have been prepared and used for various applications. Room temperature molten electrolytes consisting of magnesium perchlorate/magnesium triflate as one of the constituents have been used for rechargeable magnesium batteries where as those consisting of zinc perchlorate /zinc triflate have been used for zinc based rechargeable batteries. Full utilization of cathode material (y-mno2) is achieved using amide-based molten liquid as electrolyte in rechargeable zinc based batteries. Ammonium nitrate/ lithium nitrate containing electrolytes have been used for electrochemical super capacitors. They have been used as solvent cum stabilizers for metallic nanochains that can be used as substrate in surface enchanced Raman scattering studies.
2

Electrolyte for high energy- and power-density zinc batteries and ion capacitors

Chen, Peng, Sun, Xiaohan, Pietsch, Tobias, Plietker, Bernd, Brunner, Eike, Ruck, Michael 22 February 2024 (has links)
Growth of dendrites, limited coulombic efficiency (CE), and the lack of high-voltage electrolytes restrict the commercialization of zinc batteries and capacitors. These issues are resolved by a new electrolyte, based on the zinc(II)–betaine complex [Zn(bet)2][NTf2]2. Solutions in acetonitrile (AN) avoid dendrite formation. A Zn||Zn cell operates stably over 10 110 h (5055 cycles) at 0.2 mA cm−2 or 110 h at 50 mA cm−2, and has an area capacity of 113 mAh cm−2 at 80% depth of discharge. A zinc–graphite battery performs at 2.6 V with a midpoint discharge-voltage of 2.4 V. The capacity-retention at 3 A g−1 (150 C) is 97% after 1000 cycles and 68% after 10 000 cycles. The charge/discharge time is about 24 s at 3.0 A g−1 with an energy density of 49 Wh kg−1 at a power density of 6864 W kg−1 based on the cathode. A zinc||activated-carbon ion-capacitor (coin cell) exhibits an operating-voltage window of 2.5 V, an energy density of 96 Wh kg−1 with a power density of 610 W kg−1 at 0.5 A g−1. At 12 A g−1, 36 Wh kg−1, and 13 600 W kg−1 are achieved with 90% capacity-retention and an average CE of 96% over 10 000 cycles. Quantum-chemical methods and vibrational spectroscopy reveal [Zn(bet)2(AN)2]2+ as the dominant complex in the electrolyte.

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