Mn掺杂Ni(OH)2的合成及电化学性能研究

本工作采用缓冲溶液法制备Mn掺杂Ni(OH)₂(Ni_1-xMn_x(OH)₂, x=0.1, 0.2, 0.3, 0.4), X射线衍射测试表明样品主要是β相, 有少量Mn₃O₄杂相; 循环伏安测试表明, x=0.2的材料还原峰积分面积最大、还原分支的峰电流最高; 恒流充放电测试表明, 在100 mA/g电流密度下, Ni_0.8Mn_0.2(OH)₂放电比容量最高, 其第20次循环放电比容量为271.8 mAh/g, 同等条件测试的商用β-Ni(OH)₂放电比容量为253.6 mAh/g; 在300、500 mA/g电流密度下, Ni_0.8Mn_0.2(OH)₂放电比容量仍保持最高, 分别为294.7、291.5 mAh/g, 而且Mn掺杂Ni(OH)₂的循环稳定性也优于商用β-Ni(OH)₂。Mn掺杂可改善镍电极的循环稳定性、降低镍电极成本, 具有广阔的应用前景。

Preparation and Electrochemical Performance of Mn Doped Ni(OH)2

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.