Unveiling the structural evolution of pillared graphene-based electrodes for supercapacitors during cycling by combined Operando SAXS/WAXS

We have developed pillared graphene-based materials showing promising interests for supercapacitors (SCs) applications. These materials have a complex structure resulting from the coexistence of graphene sheets restacked in graphite-like arrangement and graphene sheets spaced out using a molecular pillar controlling the inter-sheet distance and providing valuable electrolytic ions adsorption site. With the aim of identifying and understanding the adsorption mechanisms at play in the charge/discharge stages it is essential to follow the evolution of both the structure and the porosity upon polarization and cycling. However, such operando investigations necessitate synchrotron beam. Indeed, compared to batteries, SCs have much faster cycling kinetics which are incompatible with the typical required counting times of lab diffractometers. Operando SAXS/WAXS measurements using synchrotron radiation are therefore of prime interest to reveal time-resolved multi-scale structural evolution.