Ultrafast charge-discharge characteristics of a nanosized core-shell structured LiFePO4 material for hybrid supercapacitor applications

Katsuhiko Naoi, Kazuaki Kisu, Etsuro Iwama, Shota Nakashima, Yuki Sakai, Yuki Orikasa, Philippe Leone, Nicolas Dupré, Thierry Brousse, Patrick Rozier, Wako Naoi, Patrice Simon

Research output: Contribution to journalArticle

77 Citations (Scopus)

Abstract

Highly dispersed crystalline/amorphous LiFePO4 (LFP) nanoparticles encapsulated within hollow-structured graphitic carbon were synthesized using an in situ ultracentrifugation process. Ultracentrifugation triggered an in situ sol-gel reaction that led to the formation of core-shell LFP simultaneously hybridized with fractured graphitic carbon. The structure has double cores that contain a crystalline LFP (core 1) covered by an amorphous LFP containing Fe3+ defects (core 2), which are encapsulated by graphitic carbon (shell). These core-shell LFP nanocomposites show improved Li+ diffusivity thanks to the presence of an amorphous LFP phase. This material enables ultrafast discharge rates (60 mA h g-1 at 100C and 36 mA h g-1 at 300C) as well as ultrafast charge rates (60 mA h g-1 at 100C and 36 mA h g-1 at 300C). The synthesized core-shell nanocomposites overcome the inherent one-dimensional diffusion limitation in LFP and yet deliver/store high electrochemical capacity in both ways symmetrically up to 480C. Such a high rate symmetric capacity for both charge and discharge has never been reported so far for LFP cathode materials. This offers new opportunities for designing high-energy and high-power hybrid supercapacitors.

Original languageEnglish
Pages (from-to)2143-2151
Number of pages9
JournalEnergy and Environmental Science
Volume9
Issue number6
DOIs
Publication statusPublished - 2016 Jun
Externally publishedYes

ASJC Scopus subject areas

  • Environmental Chemistry
  • Renewable Energy, Sustainability and the Environment
  • Nuclear Energy and Engineering
  • Pollution

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    Naoi, K., Kisu, K., Iwama, E., Nakashima, S., Sakai, Y., Orikasa, Y., Leone, P., Dupré, N., Brousse, T., Rozier, P., Naoi, W., & Simon, P. (2016). Ultrafast charge-discharge characteristics of a nanosized core-shell structured LiFePO4 material for hybrid supercapacitor applications. Energy and Environmental Science, 9(6), 2143-2151. https://doi.org/10.1039/c6ee00829a