Effects of lithium doping on hydrogen storage properties of heat welded random CNT network structures

This paper presents the effects of lithium doping on the hydrogen storage capability of heat welded random carbon nanotube (CNT) network structures having different cross-link densities at room temperature. Cluster based and atom based doping strategies are taken into consideration in the current simulations. Moreover, different doping ratios are used in our calculations to clarify the effect of doping ratio on hydrogen uptake behavior of CNT networks. The network structures are generated by using a cyclic stochastic algorithm and covalently bonded couplings are created by applying the heat welding method via molecular dynamic simulations. Hydrogen storage capacity of the Li-doped CNT networks is investigated using Grand Canonical Monte Carlo (GCMC) simulations. The simulation results show that hydrogen storage capacity is appreciably enhanced with the presence of lithium atoms and increases as the doping ratio increases. Besides, atom based doping method is found to be more efficient in hydrogen uptake than cluster based doping method under the same doping ratio. Furthermore, our results also show that the cross-link density is a critical parameter and hydrogen storage capability of Li-doped CNT network material can be improved with the appropriate choice of cross-link density.