A single-source Co/Li/O organometallic precursor for nanocrystalline LiCoO₂ - Synthesis, formation pathway, and electrochemical performance

A single-source precursor route to phase-pure LiCoO₂ by employing the organometallic precursor [(COD)₂CoLi(thf)₂] (1) to introduce a Co/Li/O 1:1:2 stoichiometry is described for the first time. Compound 1 undergoes decomposition in the presence of oxygen, forming nanoscaled, electrochemically active LiCoO₂ starting at a temperature as low as 200 °C. Its temperature-dependent formation pathway was studied by various spectroscopic and microscopic techniques. The transition temperature for the evolution of layered LiCoO₂ is above 400 °C. Electrochemical studies indicate that the low-temperature modification of LiCoO₂ can be obtained at 500 °C, showing moderate electrochemical battery performance. The single-source organometallic precursor, [bis(η-1,5-cyclooctadiene)cobaltlithium], containing Li, Co, and O in the exact 1:1:2 atomic ratio, allows synthesis ofelectrochemically active nanocrystalline LiCoO₂ at moderate temperatures.