| Abstract
| - Co3O4 nanocrystals were precipitated from aqueous solutions, forming compact porous micrometric agglomerates. Once the electrode process is optimized, these powders show improved electrochemical behavior vs Li compared to non-organized nanocrystals. This led to a better understanding of the first cycle irreversible loss, the main systematic drawback for conversion reactions.
- Oxidative precipitation in an aqueous medium of highly self-compacted crystallized Co3O4 densenanoparticles (4−5 nm) leads to the formation of porous micrometric agglomerates exhibiting a well-defined porosity distribution. Postannealing of these powders induces drastic reorganizations first becauseof the fast removal of trapped water and then because of the particles sintering, resulting in larger inter-particle voids. Electrochemical behavior of this nanometric material precipitated at moderate temperatureis found to be extremely dependent on the way the mixing with the SP conducting carbon is performed;the better performances being obtained by a soft mixing in an organic solvent. This textural effect providesa stable capacity over the first cycles (800 mA·h/g) and reveals a first cycle capacity loss of the sameextent as for bulk Co3O4, implying that the nanotexturation undergone by bulk oxide particles duringtheir first formatting cycle is not responsible for the corresponding initial loss. Through chemical analysisof the electrolyte we found that the long-term capacity fading of our materials can be mainly attributedto the dissolution of the active material within the organic electrolyte.
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