The electrochemical hydrogen storage of multi-walled carbon nanotubes synthesized by chemical vapor deposition using a lanthanum nickel hydrogen storage alloy as catalyst

Abstract

The electrochemical hydrogen storage of multi-walled carbon nanotubes (MWNTs) has been investigated. The MWNTs were synthesized by chemical vapor deposition using a lanthanum nickel alloy as catalyst in a C2H2/H2 atmosphere. The purified MWNTs have a high hydrogen storage capacity of 380mAh/g under a condition of 200mA/g charging current density and 100mA/g discharging current density. The discharging curve has an approximate voltage plateau of 0.8V. The discharging capacity is increased as the number of cycles rises from 1 to 41. These curves showed a good and stable charging/discharging performance of CNTs. We have also investigated the effect of the weight ratio of carbon nanotubes (CNTs) to Ni on the discharging capacity of CNTs–Ni electrodes, and found that the optimum ratio is 1:9 in our experimental range. Furthermore, the polarization behavior of CNTs was studied, which exhibited that CNTs using lanthanum nickel alloy as catalyst have better electrochemical activation.