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

By Lung-Hao Hu, Feng Yu Wu, Cheng Te Lin, Andrei N. Khlobystov, Lain-Jong Li*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

376 Scopus citations

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.

Original languageEnglish (US)
Article number1687
JournalNature Communications
Volume4
DOIs
StatePublished - May 20 2013

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Chemistry(all)
  • Physics and Astronomy(all)

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