Synthesis of Li2CoSiO4 nanoparticles and structure observation by annular bright and dark field electron microscopy

Abstract

Nanocrystalline Li₂CoSiO₄ particles have been successfully synthesized via a supercritical fluid process. The as-synthesized and heated particles were 50–250 nm in diameter and were well dispersed as observed by high resolution transmission electron microscopy (HRTEM). Energy dispersive spectroscopy (EDS) and elemental mapping by scanning transmission electron microscopy (STEM) show the purity and homogenous elemental distribution of the Li₂CoSiO₄ particles. The high resolution transmission electron microscopy (HRTEM) images show well resolved lattice fringes of the crystalline Li₂CoSiO₄ particles. The structure of the Li₂CoSiO₄ particles has been determined for the first time by annular bright field-scanning transmission electron microscopy (ABF-STEM) and high angle annular dark field-scanning transmission electron microscopy (HAADF-STEM). The results revealed a tetrahedral arrangement of CoSiO₄ in the Li₂CoSiO₄ structure. The electrochemical performance results support the idea that this material has potential as a positive electrode for use in a lithium ion battery.