Influence of structural and chemical environmental factors on electrochemical hydrogen storage in carbon materials

The influences of pore size, specific surface area, and surface chemistry of carbon material as well as the pH value of electrolyte solution on the electrochemical hydrogen storage performances are investigated. Three types of carbon materials carrying micro-, meso- and macro- pores, respectively, were either commercial available or synthesized through the hard template method. Their electrochemical hydrogen storage behaviors are studied in acidic, neutral, and alkaline solutions. The results indicate that microporous carbon with a high specific surface area has great advantages in hydrogen storage capacity, stability, and cycle performance. Moreover, nitrogen-doped porous carbon can not only improve hydrogen storage capacity but also both rate and hydrogen storage stability. The neutral electrolyte provides a larger voltage window while the alkaline media exhibits positive impacts on the hydrogen storage capacity. At the same time, regardless of the pH value of the electrolytes, the larger the specific surface area of the carbon material, the higher the hydrogen storage capacity.