Small capacity decay of lithium iron phosphate (LiFePO4) synthesized continuously in supercritical water: Comparison with solid-state method

Seung Ah Hong, Su Jin Kim, Jaehoon Kim, Kyung Yoon Chung, Byung Won Cho, Jeong Won Kang

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42 Citations (Scopus)

Abstract

Nanosize lithium iron phosphate (LiFePO4) particles are synthesized using a continuous supercritical hydrothermal synthesis method at 25 MPa and 400 °C under various flow rates. The properties of LiFePO 4 synthesized in supercritical water including purity, crystallinity, atomic composition, particle size, surface area and thermal stability are compared with those of particles synthesized using a conventional solid-state method. Smaller size particles ranging 200-800 nm, higher BET surface area ranging 6.3-15.9 m2 g-1 and higher crystallinity are produced in supercritical water compared to those of the solid-state synthesized particles (3-15 μm; 2.4 m2 g-1). LiFePO4 synthesized in supercritical water exhibit higher discharge capacity of 70-80 mAh g-1 at 0.1 C after 30 cycles than that of the solid-state synthesized LiFePO4 (60 mAh g-1), which is attributed to the smaller size particles and the higher crystallinity. Smaller capacity decay at from 135 to 125 mAh g-1 is observed during the 30 cycles in carbon-coated LiFePO4 synthesized using supercritical water while rapid capacity decay from 158 to 140 mAh g-1 is observed in the carbon-coated LiFePO4 synthesized using the solid-state method.

Original languageEnglish
Pages (from-to)1027-1037
Number of pages11
JournalJournal of Supercritical Fluids
Volume55
Issue number3
DOIs
Publication statusPublished - 2011 Jan 1

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Keywords

  • Cathode active material
  • Lithium iron phosphate
  • Solid-state method
  • Supercritical hydrothermal synthesis

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Chemical Engineering(all)
  • Condensed Matter Physics

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