Spremembe notranje odpornosti litij-žveplovih baterij pri uporabi elektrolitov na osnovi ionske tekočine [DEME] [TFSI], sulfolana ali topila TEGDME
Spremembe notranje odpornosti litij-žveplovih baterij pri uporabi elektrolitov na osnovi ionske tekočine [DEME] [TFSI], sulfolana ali topila TEGDME
Changes in internal resistance of lithium-sulfur batteries when using electrolytes based on ionic liquid [DEME][TFSI], sulfolane or TEGDME solvent
ANALI PAZU 11(2021) Št./No. 1-2 strani/pages 64-71
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Povzetek: Tehnika impedančne spektroskopije je bila uporabljena za študijo notranje upornosti litijžveplovih akumulatorjev. Da bi razumeli vpliv različnih topil pogosto uporabljanih v elektrolitih za Li-S akumulatorje, so bili v raziskavi uporabljeni trije različni elektroliti (na osnovi ionske tekočine [DEME] [TFSI], topila sulfolan, ali topila TEGDME). Spremembe v notranji upornosti smo spremljali na več točkah praznjenja in polnjenja celic ter čez 50 ciklov delovanja. Iz impedančnih spektrov so bili preko analize in prileganja z enostavnim ekvivalentnim vezjem razločeni štirje impedančni prispevki, ki so bili pripisani elektrolitu, procesom na anodi ali procesom na katodi. Narejena je bila analiza sprememb v velikostih teh prispevkov in primerjava med različnimi uporabljenimi elektroliti
Ključne besede: litij-žveplovi akumulatorji; polisulfidi; impedančna spektroskopija; ionska tekočina; elektroliti.
Abstract: Internal resistance of lithium-sulfur batteries was investigated with impedance spectroscopy. In order to understand the effect of various common solvents for Li-S battery preparation, the electrolyte in the cells was varied (ionic liquid [DEME][TFSI], sulfolane or TEGDME solvent). The impedance changes were followed at several points during discharge and charge of the batteries and through 50 cycles of their use. The resulting spectra were analyzed and fitted, extracting information on four different impedance contribution. The contributions were assigned to the electrolyte, anode or cathode. Their change through a single cycle and through multiples cycles of battery use was evaluated as well as compared between cells employing different electrolytes.
Key words: lithium-sulfur batteries; polysulfides; impedance spectroscopy; ionic liquid; electrolytes.