Adaptive ionic moieties for electrolyte structural design
In the authors' words
Ionic liquids (ILs) are now an established and ubiquitous material class. In energy applications and electroresponsive lubrication, their interfacial self-assembly is crucial for their properties. This in turn is determined by chemical structure and a local hierarchy of Coulombic, van der Waals, and solvophobic interactions. We hypothesize that delocalization of the ionic charge permits the Coulombic interactions to adapt to other self-assembly imperatives, promoting both bulk and interfacial self-assembly structures and enhancing double layer responses. Novel chelated bis(catecholato)borate anion architectures are introduced, with [P 66614 ] cations. Small/wide-angle x-ray scattering of the ILs indicates pronounced cation assemblies. In the electrolyte solvent propylene carbonate, small-angle neutron scattering shows marked anion-dependent self-assembly modulation. Neutron reflectivity reveals analogous response in the electrochemical double layer; the catechols form thicker and more electroresponsive interfacial layers. Density functional theory calculations demonstrate electronic resonance, modulating the anion polarizability. This direct self-assembly control broadly affects electrochemistry, lubrication, and formulation design.
Appeared: Sunday, September 27. Science Advances. Peer-reviewed journal.