Electron and phonon properties and gas storage in carbon honeycomb

TL;DR

This study investigates the electronic, phonon, and gas storage properties of newly synthesized three-dimensional carbon honeycomb structures, revealing their potential for low thermal conductivity and high gas storage capacity.

Contribution

It provides first-principles calculations of the electronic and phonon properties of carbon honeycomb networks, highlighting their unique transport channels and gas storage capabilities.

Findings

Electrons can reach velocities of ~10^6 m/s in the networks.

Phonon transport is highly anisotropic with low thermal conductivity.

High gas storage capacity aligns with experimental results.

Abstract

A new kind of three-dimensional carbon allotropes, termed carbon honeycomb (CHC), has recently been synthesized [PRL 116, 055501 (2016)]. Based on the experimental results, a family of graphene networks are constructed, and their electronic and phonon properties are calculated by using first principles methods. All networks are porous metal with two types of electron transport channels along the honeycomb axis and they are isolated from each other: one type of channels is originated from the orbital interactions of the carbon zigzag chains and is topologically protected, while the other type of channels is from the straight lines of the carbon atoms that link the zigzag chains and is topologically trivial. The velocity of the electrons can reach ~10^6 m/s. Phonon transport in these allotropes is strongly anisotropic, and the thermal conductivities can be very low when compared with graphite by at least a factor of 15. Our calculations further indicate that these porous carbon networks possess high storage capacity for gaseous atoms and molecules in agreement with experiment.