Although lithium-ion battery technology is well established, the progress in this field relies in the development of new materials with higher energy content than that of conventional electrodes. Therefore, the replacement of graphite negative electrodes with lithium metal alloys would be highly attractive. However, the high volume changes related to the insertion/removal of lithium limit the cycle-life of the electrodes. To our knowledge, the several attempts such as the use of nanometric materials and of intermetallic compounds and composites, to control the destructive effect induced by the volume changes have not been decisive so far. Lithiation/delithiation of Cu6Sn5 both electrochemically and mechanochemically prepared on a carbon paper (CP) current collector was investigated by repeated galvanostatic cycles with time-limited charges to insert different amounts of lithium per Sn mol (Li/Sn) into the alloy. The results demonstrated that, unlike Cu6Sn5 electrodeposited on Cu foil, both electrochemical and mechanochemical Cu6Sn5 on CP can undergo hundreds of lithiathion/delithiation cycles with Li/Sn > 2 at high current density (0.74 mA cm-2), thereby delivering constant amounts of charge with coulombic efficiency near 100%. The Cu6Sn5/CP electrodes with loading of 6.6 mg cm-2 and charge limited to 2.43 Li/Sn yielded a specific capacity of 330 mAh g-1 and a capacity for geometric area of 2.18 mAh cm-2, which compare well with the values of graphite-based anodes of commercial batteries. The significant improvement on cyclability performance of the Cu6Sn5/CP electrodes is due to the carbon paper current collector’s three-dimensional conductive matrix, which preserves the electric contact over cycling so that alloy cracking become less detrimental for the electric contact.

Cycling stability of a Cu6Sn5 negative electrode for lithium ion batteries with carbon paper as current collector.

ARBIZZANI, CATIA;MASTRAGOSTINO, MARINA
2004

Abstract

Although lithium-ion battery technology is well established, the progress in this field relies in the development of new materials with higher energy content than that of conventional electrodes. Therefore, the replacement of graphite negative electrodes with lithium metal alloys would be highly attractive. However, the high volume changes related to the insertion/removal of lithium limit the cycle-life of the electrodes. To our knowledge, the several attempts such as the use of nanometric materials and of intermetallic compounds and composites, to control the destructive effect induced by the volume changes have not been decisive so far. Lithiation/delithiation of Cu6Sn5 both electrochemically and mechanochemically prepared on a carbon paper (CP) current collector was investigated by repeated galvanostatic cycles with time-limited charges to insert different amounts of lithium per Sn mol (Li/Sn) into the alloy. The results demonstrated that, unlike Cu6Sn5 electrodeposited on Cu foil, both electrochemical and mechanochemical Cu6Sn5 on CP can undergo hundreds of lithiathion/delithiation cycles with Li/Sn > 2 at high current density (0.74 mA cm-2), thereby delivering constant amounts of charge with coulombic efficiency near 100%. The Cu6Sn5/CP electrodes with loading of 6.6 mg cm-2 and charge limited to 2.43 Li/Sn yielded a specific capacity of 330 mAh g-1 and a capacity for geometric area of 2.18 mAh cm-2, which compare well with the values of graphite-based anodes of commercial batteries. The significant improvement on cyclability performance of the Cu6Sn5/CP electrodes is due to the carbon paper current collector’s three-dimensional conductive matrix, which preserves the electric contact over cycling so that alloy cracking become less detrimental for the electric contact.
Giornate dell'Elettrochimica Italiana - GEI 2004
O29
O29
C. Arbizzani; M. Lazzari; M. Mastragostino
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11585/24353
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