Cobalt oxide hollow nanoparticles as synthesized by templating a tri-block copolymer micelle with a core–shell–corona structure: a promising anode material for lithium ion batteries

Abstract

A cobalt oxide (Co₃O₄) hollow nanosphere has been fabricated by templating a micelle of an anionic tri-block copolymer, poly(styrene-block-methacrylic acid-block-ethyleneglycol) (PS-PMA-PEG), which has a core–shell–corona structure in aqueous solutions. TEM images indicate that the inner diameter of the nanosphere is ca. 30 ± 2 nm, which is corresponding to the diameter of the PS core (ca. 30 ± 2 nm) of the template micelle. The outer diameter is about ca. 60 ± 3 nm, and the thickness of the shell is around 15 ± 1 nm, which could prevent rupture during application. The Co₃O₄ hollow nanosphere was then applied to lithium ion batteries, and showed promising electrochemical properties as anode materials (>500 mA h g⁻¹ after 30 cycles).