Reversible hydrogen storage of multi-wall carbon nanotubes doped with atomically dispersed lithium

The doping of dispersed lithium (Li) onto multi-wall carbon nanotubes (CNTs) was performed by a solution method for hydrogen storage. The sample with a Li content of 1.2 wt% shows a maximal reversible hydrogen storage capacity of 3.9 wt% at 77 K and 106.66 kPa, which exceeds that of the un-doped CNTs by three times. According to the analyses of X-ray photoelectron spectroscopy, adsorption heat and nitrogen adsorption isotherms, the strong interaction between hydrogen molecules and the Li-doped CNTs, as well as the better charge isolation state of Li, may contribute to the improved hydrogen storage capacity. However, excessive Li may result in a lowering of the charge isolation state and a decrease in specific surface area and pore volume, and thus deteriorate the hydrogen storage capacity.