Simultaneous Wide and Small Angle Operando Neutron Total Scattering to Probe Electrolyte Ordering in Supercapacitors

Energy in supercapacitors is stored in the so-called electrical double layer (EDL)
of adsorbed ions on high surface area electrodes. However, despite its immense
importance for supercapacitors, the structure of EDL has never been measured
in atomistic detail due to a lack of suitable methods.
Atomistically-resolved measurements of these systems can only be provided by
neutron scattering augmented using multiple isotopically-distinct datasets,
analysed with the aid of models. Small-angle scattering gives details of the pore
structure in the electrodes, with changes in intensity directly related to
electrolyte composition in the pores. Analysis of the wide angle scattering
reveals the solvation structure of the ions and the organisation of the ions and
of hydrogen-containing solvents at the electrode surfaces that underpin charge
storage
This 4-year PhD project will develop an operando electrochemical cell to make
detailed measurements of the EDL in supercapacitors on NIMROD as a function
of charge. A further development will be the enhancement of simulation-based
analysis tools specific to high surface area and charged materials, helping to
elucidate the structure and mechanism of EDL formation.