CO₂ assisted synthesis of highly dispersed Co₃O₄ nanoparticles on mesoporous carbon for lithium ion battery

Co₃O₄ nanoparticles were uniformly dispersed onto the mesoporous carbon support (Co₃O₄/mC) using a facile process in CO₂-expanded ethanol (CE) solution. During the synthesis, CO₂ played the dual roles, one is to provide a simple physical expansion to evenly disperse the precursors onto the mesoporous carbon support, and the other is to offer some chemical groups such as CO₃^2- to facilitate the complete and uniform deposition through the coordination to the metallic cations with these anions. When used as anode material for lithium ion batteries (LIBs), the Co₃O₄/mC synthesized in CO₂-expanded ethanol solution exhibited larger surface area and better cycle performance compared with the reference sample synthesized in pure ethanol. The enhanced cycle performance could be attributed to the synergistic effects between the superior structures of mesoporous C support and the highly dispersed Co₃O₄ nanoparticles. More importantly, the synthesis of Co₃O₄/mC composite in CE solution was green and highly efficient, avoiding the use of precipitant and the aggregation of Co₃O₄, which would definitely enrich the strategies for the fabrication of carbon-based transition-metal oxide composites with great applications.