Self-assembled synthesis of hierarchical nanostructured CuO with various morphologies and their application as anodes for lithium ion batteries

We report a simple self-assembled synthesis of hierarchical CuO particles with various morphologies such as leaf, shuttle, flower, dandelion, and caddice clew. The morphologies can be easily tailored by adjusting the pH value. The synthesis is based on dehydration and re-crystallization of precursor Cu(OH)₂ nanowires. [Cu(NH₃)₄]²⁺ and OH⁻ in the solutions are considered as the key factors to influence the assembling manner of CuO. The obtained hierarchical CuO particles serve as a good model system for the study as anodes for lithium ion batteries. Various morphologies of CuO particles result in different electrochemical performances of electrodes. Compared to others, dandelion-like and caddice clew-like CuO exhibit reversible discharge capacities of 385 mAh g⁻¹ and 400 mAh g⁻¹ at 0.1 C, 340 mAh g⁻¹ and 374 mAh g⁻¹ at 0.5 C after 50 cycles, respectively. The higher discharge capacities and better cycling performances are attributed to their larger surface area and porosity, leading to better contact between CuO and electrolyte and shorter diffusion length of lithium ions.