Surface behavior of pasted nickel electrodes with electrodeposited Co-Ce on substrate
(Department of Applied Chemistry, Harbin Institute of Technology,
Harbin 150001, China)
Harbin 150001, China)
Abstract: MH/Ni battery for electro-vehicle has become a hot topic of studies. The Co-Ce alloys were electrodeposited on the nickel substrate to modify pasted nickel electrode substrate. SEM and XRD results show that the surface of the substrate contains Co(OH)2 and CoOOH film, and CV shows that modified film can improve electron conductivity capability. The state of charge (SOC) or state of discharge (SOD) curves indicate that Co-Ce modified substrate can enhance Ni electrode charge and discharge performance at high rate. The surface analysis by XPS shows that, the Co(Ⅱ)/Co(Ⅲ) ratio is 76.80/23.19 at the SOD, but the Co(Ⅱ)/Co(Ⅲ) ratio is 57.79/42.21 at the SOC, which indicates that the conductibility of electrodeposited Co-Ce alloys on the nickel substrate is enhanced because CoOOH and Co(OH)2 are created on the substrate surface. The modified surface with CoOOH and Co(OH)2 can enhance the conductibility of electrons between the substrate and active materials, and improve the high rate SOC and SOD ability.
Key words: nickel electrode; substrate modification; Co-Ce alloys; surface