The influence of stacking faults on hydrogen storage in TiCx

The hydrogen storage ability of TiC_x with stacking faults (SFs) is studied in this work. It is found that the absorption of hydrogen atoms is possible in both TiC_x with and without SFs. And, besides the carbon vacancy sites, the hydrogen atoms can also occupy the tetrahedral sites in the SFs layers. More importantly, it is confirmed that the diffusion of hydrogen in TiC_x with SFs is much easier than that in TiC_x without SFs, especially the diffusion around the SFs layers. The energy barrier for diffusion of the hydrogen atom in the SFs layers and diffusion from the SF layer to the next layer is only 0.099 eV and 0.185 eV, respectively. Therefore, bringing in the SFs in TiC_x with ordered carbon vacancies will be an effective method to solve the diffusion problem during the processes of hydrogen storage.