LiCoO

LiCoO2, or lithium cobalt oxide, is a layered transition metal oxide that has been a widely used cathode material for lithium-ion batteries. In its charged state, lithium ions are extracted from the Li layer and travel through the electrolyte during discharge as they reinsert into the structure. The material consists of cobalt in octahedral coordination with oxygen, forming CoO2 layers separated by lithium layers. The resulting structure supports relatively high energy density and good electronic conductivity.

In terms of performance, LiCoO2 has a theoretical capacity of about 274 mAh per gram and a typical operating voltage around 3.7–4.2 V versus Li/Li+. Practical capacities in commercial cells are often lower due to structural and safety considerations. The material is most stable at moderate states of charge; high states of charge can lead to structural changes and thermal instability if not properly managed.

Synthesis and processing generally involve solid-state reactions between lithium and cobalt precursors, such as Li2CO3 and Co3O4 or CoO, at high temperatures. The material has been used extensively in portable electronics and early lithium-ion batteries, including those in smartphones and laptops. In electric vehicles, LiCoO2 has been largely supplanted for high-energy applications by nickel-rich layered oxides, though it remains of interest for certain applications and research.

Safety and environmental considerations include cobalt supply risks and recycling needs. LiCoO2 can release oxygen and decompose at high temperatures or high charge voltages, underscoring the importance of thermal management and protective strategies in battery design.