Sea-Urchin-like Cobalt Oxide Grown on Nickel Foam as a Carbon-Free Electrode for Lithium–Oxygen Batteries

Abstract

Rechargeable lithium–oxygen batteries have attracted extensive attention for their high energy density. However, the carbon corrosion, the undesired electrolyte decomposition catalyzed by carbon, and the irreversible reaction between carbon and the discharge product Li2O2 limit their performance. Herein we show the synthesis of sea-urchin-like cobalt oxide growing directly on nickel foam by a facile method, exhibiting several features. First, the open structure facilitates electrolyte penetration and the ion/electron transfer. Furthermore, the macrosized voids built up by the 1D nanorods provide sufficient buffer space for Li2O2 deposition without blocking O2 diffusion. As a result, the battery displays high performance, including a high specific capacity of ∼3000 mAh g–1 based on the weight of the whole electrode and long-life (∼1800 h, 60 cycles at a fixed capacity of 500 mAh g–1).