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Nano-Ni(OH)2 doped with special elements were prepared by supersonic co-precipitation method. Complex electrodes were prepared by immersion method and handwork method by mixing 8wt.% nickel hydroxides with commercial micro-size spherical nickel as the positive material of Ni-MH battery. The electrochemical performance and cyclic character affected by different electrodes’ making methods were characterized in this article. The result indicates that the discharge capacities of IM electrodes (IM electrodes mean electrodes made by handwork method) are higher than that of HM electrodes (HM electrodes mean electrodes made by handwork method). Furthermore, IM electrodes have better reversibility and higher charge efficiency than HM electrode, and lower charge potential and higher discharge plateau were also observed for IM electrodes. It's worth noting that the phenomenon is more obvious at high charge/discharge rate. When the discharge rate is 0.5C，the discharge capacity of IM electrode is higher 67.1 mAh•g -1 than that of HM electrode.

Co substituted nanonickel hydroxide, which used NiCl 2 and Na 2 CO 3 as nickel source and buffer respectively, was synthesised by ultrasonic method. XRD, TEM, PSD and EDS were used to characterise the physical and electrochemical performance of the prepared samples respectively. The electrochemical performance affected by Co substituted ratio and buffer content were determined by cyclic voltammogram and discharge-charge test. The results demonstrated that the Co substituted nanonickel hydroxide was the mixed phase of a-and b-Ni(OH) 2 and the increasing Co content led to the larger proportion of a-nickel hydroxide. An increase in Na 2 CO 3 content was beneficial to form a-nickel hydroxide. The morphology of all samples was the needlelike and the length/diameter ratio decreased with increasing Na 2 CO 3 content. Composite electrodes were made by mixing 8 wt-% nickel hydroxide with commercial b-nickel hydroxide. The discharge capacities of electrodes first increased and then decreased with the change of Na 2 CO 3 content. When Ni 2z was 0?4 mol L 21 and Na 2 CO 3 was 0?5 g, the electrode had the maximum discharge capacity, which reached 306?9 mAh g 21 at 0?5 C discharge/charge rate.