Template-free synthesis of hierarchical porous Co3O4 microspheres and their application for electrochemical energy storage

• Construct Co3O4 nanoflake microspheres by a template-free method.
• Co3O4 nanoflake microspheres show high capacity and good cycling life.
• Nanoflake microspheres are favorable for fast ion and electron transfer.

Tailored high-activity cathode materials are of great importance for construction of high-performance capacitors and hybrid batteries. In this work, we report a facile template-free chemical bath deposition method to fabricate porous Co3O4 nanoflake microspheres consisting of self-assembled nanoflakes with thicknesses of ∼10 nm. The as-prepared Co3O4 microspheres have average diameters of ∼2 μm and the secondary Co3O4 nanoflakes are interconnected with each other forming a highly open net-structure with pore diameters of 20-200 nm. When evaluated as cathode materials for pseudocapacitive hybrid batteries, the Co3O4 nanoflake microspheres deliver a specific capacity of 83 mAh g−1 at 1 A g−1 after 10,000 cycles, higher than the Co3O4 nanowire microspheres counterpart (70 mAh g−1). In addition, the electrode exhibits excellent long-term cycling stability with 94.5% capacity retention after 10,000 cycles at 1 A g−1. The enhancement of high-rate electrochemical performances is due to the unique nanoflake microspheres architecture with large surface area and open porous structure.

We report a facile template-free chemical bath deposition method for the growth of Co3O4 nanoflake microspheres and demonstrate noticeable electrochemical properties with higher capacities and better cycling life than the nanowire counterparts.Figure optionsDownload as PowerPoint slide