Intercalation in Layered Materials

• Intercalation is a reversible insertion of mobile atomic or molecular guest species into a solid host lattice

• Intercalation compounds are hybrid systems between solids and fluids

• Most visible effect: Host lattice expansion

• Host intralayer structure remains unchanged

• Strong bonding WITHIN layers (covalent)

• Weak bonding BETWEEN layers (‘galleries’, ‘van der Waals gaps’)

• Intercalation leads to a broad spectrum of compounds
• Most important classes:
  transition-metal dichalcogenide IC’s (TMDIC’s)
  graphite IC’s (GIC’s)
• Variety of unusual chemical and physical properties
  superconductivity, charge density waves, anisotropic
  electrical conductivity, redox reactions, structural transitions, superstructures
• Ideal arena for studying physical phenomena in 1 and 2 dimensions
• Phenomenal synthetic flexibility
• Controlled modification of physical properties of solids
• Low temperature pathway to synthesize new materials
• Alternative for thin-film superlattices
• Applications:
  battery electrodes, electrochemic displays, catalysis, dry lubricants, and sensor systems