From small backup power supplies in hand held electronics to regenerative braking in heavy good vehicles, electrical energy storage is becoming more important, and more pervasive within modern technology. Electrochemical double layer capacitors (EDLCs) are a high power energy storage device that operate by charge separation across the double layer at the electrode/electrolyte interface. To continue improving these devices we must further our understanding of the structure of the electrolyte ions at the electrode surface. Graphene is one of a number of carbons used for EDLC electrodes. This proposal aims to investigate the interactions and absorption of ions on graphene substrates utilising the unique capability of neutron reflection to study surface structures of organic molecules on carbon surfaces. The structures adopted with and without applied potential will be studied.