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Nat Commun. 2013;4:1687. doi: 10.1038/ncomms2705.

Graphene-modified LiFePO₄ cathode for lithium ion battery beyond theoretical capacity.

Author information

1
Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan.

Abstract

The specific capacity of commercially available cathode carbon-coated lithium iron phosphate is typically 120-160 mAh g(-1), which is lower than the theoretical value 170 mAh g(-1). Here we report that the carbon-coated lithium iron phosphate, surface-modified with 2 wt% of the electrochemically exfoliated graphene layers, is able to reach 208 mAh g(-1) in specific capacity. The excess capacity is attributed to the reversible reduction-oxidation reaction between the lithium ions of the electrolyte and the exfoliated graphene flakes, where the graphene flakes exhibit a capacity higher than 2,000 mAh g(-1). The highly conductive graphene flakes wrapping around carbon-coated lithium iron phosphate also assist the electron migration during the charge/discharge processes, diminishing the irreversible capacity at the first cycle and leading to ~100% coulombic efficiency without fading at various C-rates. Such a simple and scalable approach may also be applied to other cathode systems, boosting up the capacity for various Li batteries.

PMID:
23575691
DOI:
10.1038/ncomms2705

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