Syntheses of LiCoO₂ mesocrystals by topotactic transformation and their electrochemical properties

Synthetic routes for LiCoO₂ mesocrystals with porous and single-crystalline structures through the topotactic transformation of precursor crystals are developed. Octahedral LiCoO₂ frameworks of 4-6 μm in diameter, consisting of 600-800 nm subunits, are obtained from octahedral solid particles of Co₂(OH)₃Cl. Hollow LiCoO₂ plates about 600 nm wide and 40 nm thick composed of 100-400 nm subunits are produced from hexagonal disks of β-Co(OH)₂. The LiCoO₂ mesocrystals exhibit enhanced charge-discharge cycle stability and rate performance as a cathode material for lithium-ion batteries. The high reactive surface area, owing to the porous framework, and high lithium-ion and electron conductivities, originating from the single-crystalline nature, effectively enhance their electrochemical properties. Morph into one: New synthetic routes to LiCoO₂ mesocrystals with a porous and single-crystalline structure are developed by using topotactic transformation of precursor crystals (see picture). Octahedral LiCoO₂ frameworks and hollow LiCoO₂ plates, consisting of oriented subunits, exhibit enhanced charge-discharge cycle stability and rate performance as the cathode material of lithium-ion batteries.