Influence of Metal Substitute on Electrochemical and Sorption Characteristics of LaNi_5 Based Alloys

摘要

A systematic investigation of the substituting components' influence on kinetic, sorption characteristics and the equilibrium hydrides formation potential in the LaNi_5 system alloys in alkaline electrolyte has been conducted. It was ascertained that increasing a substituting component radius and thus growth of an elementary cell volume results in increasing enthalpy of hydrides formation and anode shift of hydrides formation equilibrium potential. This shift increases with substituting component amount increasing. It was shown that the dependence between value of the hydrides formation enthalpy and hydrides formation (decomposition) equilibrium potential is linear. Inserting Co, Mn, Al into LaNi_5 leads to the growth of surface catalytic activity relative to hydrogen exchange reaction. In consequence of this the absorption of hydrogen by the alloy become easier that allows to receive on no activated electrodes high discharge capacity (280-320 mA.h/g) even at the initial charge/discharge cycles.