High Temperature Electrochemical Performance of Al-substitutedα-Ni(OH)_2

The purpose of this study was to explore the synthesis of finer Al-substituted Ni(OH)_2 particles by means of homogeneous precipitation method and to investigate its'micro-morphology,crys- tal structure,chemical composition and electrochemical performance at high temperature.The results show that a stabilized a-phase is obtained for the experimental substance and the particles are spheri- cal agglomerates of fibrous nanometer scale crystallites.The approximate chemical composition of the product can be described as Ni_(0.70)Al_(0.18)(OH)_(1.6)(CO_3)_(0.1)(SO_4)_(0.07)·(H_2O)_(0.6).In the experimental MH-Ni batteries,Al-substituted Ni(OH)_2 anode displays high charging efficiency and good cyclic stability with comparatively high oxygen evolution potential at 60℃.Compared with the behavior at 25℃,its dis- charging capacity at 60℃is decreased by 15mAh/g.Moreover,after electrochemically cycled at 60℃for 95 times,the structure of Al-substituted Ni(OH)_2 remains mainlyαphase,showing good structural stability.