Quantum capacitance modifies interionic interactions in semiconducting nanopores
1 Mathematical Institute, University of Oxford - Woodstock Rd, Oxford, OX2 6GG, UK
2 John A. Paulson School of Engineering and Applied Sciences, Harvard University - Cambridge, MA 02138, USA
Received: 3 December 2015
Accepted: 11 February 2016
Nanopores made with low-dimensional semiconducting materials, such as carbon nanotubes and graphene slit pores, are used in supercapacitors. For modelling purposes, it is often assumed that such pores screen ion-ion interactions like metallic pores, i.e. that screening leads to an exponential decay of the interaction potential with ion separation. By introducing a quantum capacitance that accounts for the density of states in the material, we show that ion-ion interactions in carbon nanotubes and graphene slit pores actually decay algebraically with ion separation. This result suggests a new avenue of capacitance optimization based on tuning the electronic structure of a pore: a marked enhancement in capacitance might be achieved by developing nanopores made with metallic materials or bulk semimetallic materials.
PACS: 82.47.Uv – Electrochemical capacitors; supercapacitors / 73.63.Fg – Nanotubes / 73.22.Pr – Electronic structure of graphene
© EPLA, 2016