lithiumkobaltoxide

Lithiumkobaltoxide, commonly known as lithium cobalt oxide, is a layered transition metal oxide with the formula LiCoO2. It has long served as a cathode material in commercial lithium-ion batteries, offering high energy density and good rate capability at moderate voltages. Due to concerns about cobalt supply and cost, newer designs increasingly substitute it with cobalt-lean chemistries.

Its crystal structure comprises alternating CoO2 sheets and lithium-ion layers. In the discharged state cobalt is in the Co3+ state; during charging Li+ ions are extracted from octahedral sites in the Li layers, leading to oxidation of cobalt toward Co4+. The layered arrangement supports reversible insertion and removal of Li+, but the structure is susceptible to instability at high states of delithiation and elevated temperatures, which can lead to capacity fade or safety issues such as oxygen release if overcharged.

Synthesis is typically by high-temperature solid-state reaction from Li2CO3 and a cobalt oxide precursor, with careful control to minimize lithium loss and cation mixing. Performance is characterized by practical capacities around 140–170 mAh/g and average operation voltages near 3.8–4.2 V versus Li+/Li; theoretical capacity is higher but not fully realized in commercial cells. LiCoO2 is being progressively replaced or supplemented by nickel-rich layered oxides and by doped variants to lower cobalt content and improve thermal stability and longevity; recycling and responsible sourcing of cobalt are important considerations in its use.