Theelectrochemicalbehaviorofgraphiteanodes,coatedby50–500A ̊-thickSnlayers,isdiscussedin the present paper. Morphology and structure of the modified electrode surfaces are described, and the charge/discharge behavior is evaluated by galvanostatic cycles at temperatures down to −30◦C. The enhanced kinetics of the intercalation/deintercalation process is studied by cyclic voltammetry and electrochemical impedance spectroscopy, focusing on the role played by the Sn coatings in the inter- calation/deintercalation mechanism. The results show that the metal layers modify and stabilize the electrode/electrolyte interphase and that the intercalation process is mediated by reversible Li–Sn alloys formation. Moreover, all the Sn coatings are effective in modifying the energy barriers related both to the Li+ desolvation step and to the migration of the desolvated Li+ ion through the modified surface layers. As a consequence, the overall polarization for the charge-transfer process is reduced, and enhanced low-temperature intercalation performances are obtained.

Tin-coated graphite electrodes as composite anodes for Li-ion batteries. Effects of tin coatings thickness toward intercalation behavior.

NOBILI, Francesco;MARASSI, Roberto
2012-01-01

Abstract

Theelectrochemicalbehaviorofgraphiteanodes,coatedby50–500A ̊-thickSnlayers,isdiscussedin the present paper. Morphology and structure of the modified electrode surfaces are described, and the charge/discharge behavior is evaluated by galvanostatic cycles at temperatures down to −30◦C. The enhanced kinetics of the intercalation/deintercalation process is studied by cyclic voltammetry and electrochemical impedance spectroscopy, focusing on the role played by the Sn coatings in the inter- calation/deintercalation mechanism. The results show that the metal layers modify and stabilize the electrode/electrolyte interphase and that the intercalation process is mediated by reversible Li–Sn alloys formation. Moreover, all the Sn coatings are effective in modifying the energy barriers related both to the Li+ desolvation step and to the migration of the desolvated Li+ ion through the modified surface layers. As a consequence, the overall polarization for the charge-transfer process is reduced, and enhanced low-temperature intercalation performances are obtained.
2012
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11581/218490
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