Ionic liquid functionalized nanoparticles: Synthetic strategies and electrochemical applications

Functionalization of nanoparticles (NPs) has fueled the evolution of nanoscience and nanotechnology through the design of smart materials with novel properties. While simple coupling agents are sufficient to protect NPs against agglomeration, functionalizing them with ionic liquids (ILs) or similar long-chain organic molecules offers additional synergies. The resultant self-suspended nanoscale hybrid ionic fluids (NHIFs) are usually composed of an NP core and a surface modified with a charged corona and an IL-like canopy tethered to the corona by either covalent or ionic bonding. The wide parameter space available for architectural choices for this new materials platform enables incredible flexibility in physical properties and has attracted much scientific and applications interest during the last two decades. This chapter reviews different methodologies to create NHIFs with controlled distribution of different core NPs within the perspective of an exclusively IL-like canopy and addresses associated challenges. Furthermore, it surveys the physical, thermal, and electrochemical properties of these nanoscale hybrids in the contexts of two contemporary device applications: lithium batteries and supercapacitors.