Ni-Doped Carbons as a Carbon Support for Metal Hydride Electrodes

J. E. THOMAS; RITA M. HUMANA; L. ZUBIZARRETA; A. ARENILLAS; J. A. MENÉNDEZ; H. L. CORSO; A. VISINTIN

Torremolinos - España

Conferencia; Carbons for Energy Storage and Environment Protection - CESEP 09; 2009

Grupo Español del Carbón

In-lab synthesized Ni-doped carbons (i.e., nanospheres and carbon xerogels) were used as carbon support in order to study the possibility to improve the electrochemical behaviour of AB5-alloy electrodes for Nickel-Metal Hydride rechargeable batteries. The carbons used for this work were synthesized by polymerization of resorcinol and formaldehyde, in the case of carbon xerogels, and the polymerization of furfuryl alcohol in the case of nanospheres. The structure and textural properties of the carbons are completely different. These supports were carbonized and doped with different amounts of Ni by the excess solution impregnation method. Final supports were texturally characterized by adsorption-desorption of N2 and CO2 at 77 K and 273 K, respectively. The carbon structure was analyzed by XRD and TEM, and the samples composition was also characterized by elemental analysis.These carbon supports were mixed with an AB5-type alloy (MmNi4.1Co0.4Mn0.4Al0.5), Vulcan and PTFE as a binder; this mixture was pressed over a Ni mesh to make the working electrodes. Different compositions of synthesized Ni-doped carbons/PTFE were tested (15%,25% and 33%) for obtaining the best electrode performance. Charge and discharge techniques, cyclic voltammetry,rate capability and electrochemical impedance spectroscopy were used for the electrochemical characterization of the electrodes. Results show that this kind of carbons could be used as support for hydrogen storage electrodes with a good electrochemical behaviour and kinetic response.