A simple method of electrochemical lithium intercalation within graphite from a propylene carbonate-based solution

초록

Electrochemical lithium intercalation within graphite from 1 mol dm(-3) solution of LiClO4 in propylene carbonate (PC) was investigated at 25 and -15 degrees C. Lithium ions were intercalated into and de-intercalated from graphite reversibly at -15 degrees C despite the use of pure PC as the solvent. However, ceaseless solvent decomposition and intense exfoliation of graphene layers occurred at 25 degrees C. The results of the Raman spectroscopic analysis indicated that the interaction between PC molecules and lithium ions became weaker at -15 degrees C by chemical exchange effects, which suggested that the thermodynamic stability of the solvated lithium ions was an important factor that determined the formation of a solid electrolyte interface (SEI) in PC-based solutions. Charge-discharge analysis revealed that the nature of the SEI formed at -15 degrees C in 1 mol dm(-3) of LiClO4 in PC was significantly different from that formed at 25 degrees C in 1 mol dm(-3) of LiClO4 in PC containing vinylene carbonate, 3.27 mol kg(-1) of LiClO4 in PC, and 1 mol dm(-3) of LiClO4 in ethylene carbonate. (c) 2013 Elsevier B.V. All rights reserved.

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