Abstract: The chronoamperometry was used to study the powdery microelectrode made of spherical Ni(OH)₂. The effects of doping elements on the proton diffusion coefficients D_H were investigated for anode and cathode processes at 25℃. The results showed that in comparison with pure Ni(OH)₂ the anode process diffusion coefficients (D⁰) of Ni(OH)₂ doped with Co, Co+Zn and Ca were increased a little and those of doped with Zn, Fe and Mg decreased. In contrast, the cathode diffusion coefficients (D^R) of Ni(OH)₂ doped with Co and Ca were almost doubled and that doped with Fe and Mg were reduced to one fourth as compared with that of pure Ni(OH)₂. Doping of Cd only had a very small effect on the D_H for both anode and cathode. It appeared that doping of Co, Ca tends to increase the anode proton diffusion velocity, while doping of Fe and Mg tends to decrease the cathode diffusion velocity. The D_H of the anode process were found to the 2 orders of magnitude higher than that of the cathode process (10^-12 vs 10^-10 cm²/s).