Magnesium and calcium ion batteries based on the hexa-peri-hexabenzocoronene nanographene anode materials

The potential application of a hexa-peri-hexabenzocoronene (HBC) nanographene as an anode material in the Mgand Ca-ion batteries (MIBs and CIBs) was explored by means of the DFT calculations. The Mg or Ca cation chemically adsorbed over the center of the rim hexagons with the adsorption energies of -190.3 or -118.2 kcal/ mol. But the Mg or Ca atom was physically adsorbed on the HBC, releasing an energy about 4.1 or 4.8 kcal/mol. Moreover, the energy barrier which should be passed by the Mg or Ca cations to migrate from the surface of a hexagon to another is 4.2 or 5.3 kcal/mol. These small values increase the ion mobility and charge/discharge rate. The specific capacity of HBC nanographene was predicted to be 593.5 and 486.8 mAh/g for Mg and Ca atoms, respectively. The stronger cation-pi interaction between Mg2+ and the HBC generated a higher cell voltage for MIBs (3.97 V), compared to the CIBs (2.45 V). The HBC nanographene is a proper candidate to be used in MIBs and CIBs as an anode material due to different features, including high ion mobility, great cell voltage, and excessive storage capacity.

Automated summary

The potential application of hexa-peri-hexabenzocoronene (HBC) nanographene as an anode material in Mg and Ca-ion batteries was explored using DFT calculations. The results show that HBC has high ion mobility, great storage capacity, and higher cell voltage, making it a suitable candidate for use in MIBs and CIBs as an anode material.