Abstract:

Manganese doped Ni_1-xMn_x(OH)₂ (x=0.1, 0.2, 0.3, 0.4) was prepared by buffer solution method. X-ray diffraction (XRD) measurements show that the samples are mainly composed of β-Ni(OH)₂ with little amount of Mn₃O₄ phase. Cyclic voltammetry results show that the integral area of reduction peak of Ni_0.8Mn_0.2(OH)₂ is the largest among the samples. The constant current charge-discharge tests show that the discharge capacity of Ni_0.8Mn_0.2(OH)₂ reaches 271.8 mAh/g at the current density of 100 mA/g, which is higher than that of other samples and commercial β-Ni(OH)₂ (253.6 mAh/g). At the current density of 300 and 500 mA/g, Ni_0.8Mn_0.2(OH)₂ remains the highest discharge capacity of 294.7 and 291.5 mAh/g, respectively. Moreover, the cycling stability of Ni_1-xMn_x(OH)₂ is superior to commercial β-Ni(OH)₂. All data indicate that Mn doped Ni(OH)₂ can improve the capacity and cycling stability of nickel electrodes, and greatly reduce the cost of nickel electrodes.

Key words: buffer solution method, Mn doped Ni(OH)₂, cycling stability