Fullerene-like Si60C60 nanocage: Hydrogen storage capacity

• We study hydrogen storage properties of Si60C60 nanocage using DFT.
• We study the role of pressure on the number of encapsulated H2 molecules.
• The nH2@Si60C60 systems remain stable for n close to 70.
• The energy gap of the nH2@Si60C60 systems remains constant for n ≤ 70.

For investigating the hydrogen storage capacity of the Si60C60 nanocage, we have performed first principle density functional theory calculations with van der waals corrections. According to the force and energy minimization of the complex structures of nH2@Si60C60, we have found that the systems with n = 1 to 70 are energetically favorable. We also found that the most stable nH2@Si60C60 system is related to the systems with n close to 50 which make it possible to reach 4.2 wt% of hydrogen storage. Although it is found that the nH2@Si60C60 system remains stable up to n = 70 and 5.8 wt%. The NPT molecular dynamic investigation at different pressures (0–30 atm) and also different temperatures (300–1800 K) were carried out on the optimized stable system with maximum capacity of encapsulating H2 molecules (70H2@Si60C60).