Fabrication of LiCoO2 crystal layers using a flux method and their application for additive-free lithium-ion rechargeable battery cathodes

Yusuke Mizuno, Nobuyuki Zettsu, Kunio Yubuta, Takuya Sakaguchi, Toshiya Saito, Hajime Wagata, Shuji Oishi, Katsuya Teshima

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)

Abstract

Higher performance active materials containing cathodes have been strongly required for the achievement of advanced lithium-ion rechargeable batteries. We report the formation of a densely packed and idiomorphic LiCoO2 crystal layer directly on a substrate surface using flux coating with a LiNO3-LiOH mixed flux and their applications as an additive-free cathode to enhance gravimetric energy density per single cell as well as durability. The formation mechanism of LiCoO2 nanocrystals from high temperature melt of the mixed flux was controlled under evolution selection growth, driven by supersaturation. The as-grown crystals formed a petal-shape with well-developed {001} faces. After annealing treatment, the crystal shape transformed into hexagonal plates with vertical orientation. The hexagonal plate-shaped crystal arrays were identified to be homogeneous LiCoO2 having a rhombohedral crystal system. Their lattice parameters were a = 0.2784 and c = 1.4248 nm, and the Li/Co ratio in the crystals was 1.00. Furthermore, transmission electron microscopic images and selected area electron diffraction patterns revealed that the interface between the crystal layer and the substrate was smoothly connected and free of impurities. In fact, the LiCoO2 nanoplate layer exhibited desirable properties such as a large discharge capacity close to its theoretical value, higher rate performance, and high cyclability over 500 cycles with no assistance of additional electroconductive materials and binders, meaning that the interfaces provide seamless charge transportation pathways.

Original languageEnglish
Pages (from-to)1882-1887
Number of pages6
JournalCrystal Growth and Design
Volume14
Issue number4
DOIs
Publication statusPublished - 2014 Apr 2

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

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