Molekylära miljöer för alkalijoner i batterier. Att särskilja träden i en skog

I plan to use NMR metods to characterize the molecular environments of alkali ions such as the lithium and sodium ions in various components of alkali-ion batteries, a family of energy-storage devices where today the lithium-ion battery is the dominant member. One of the two components I shall concentrate on is the anode and, specifically, hard carbons as anodes.

The structure of hard carbon is not well characterized and the sites at which the ions are stored are understood even less.

The other component is the solid-electrolyte interphase, the passivating and ion-conducting layer on the anode thay is similarly poorly understood with regard of its molecular and mesoscopic structure.

Based on prelimanry results, I propose that by investigating the temperature dependence of the 7Li and 23Na spectra one can establish the temperature range where the detectable spectral parameters such as the frequency shift and the quadrupole splitting reflect the local properties of the ion coordination sites.

Having established that, one can perform exchange experiments with the help of, for example, spin alignment echoes and nutation techniques.

Those experiments provide information about how does the structure of coordination sites is distributed spatially within either hard carbon or the solid-electrolyte interphase.

Such insights, together with supporting data from eg 13C spectra of the hard carbon matrix and XRD can open a new window on the structures present in those complex materials.