Mecanismos de armazenamento de energia no Ni(OH)2

The nickel hydroxide can be considered an material that develops extrinsic pseudocapacitance. The total value of capacitance in this material includes capacitive and battery- type contribution. In this work, we focus on a deeper understanding of the various contributions to the total charge stored at different scan rates. For this, was obtained Ni(OH)2 by a method of electrodeposition and at temperatures of 10 and 25 oC. To analyze the different contributions charge storage, a detailed voltammetric study is conducted, related to a study of spectroscopy electrochemical impedance. The area surrounded within the CV curve of the films obtained to 10 oC is obviously larger than that of the films obtained to 25 oC, indicating that more active materials were involved in the reaction. Was determined the total charge stored for samples, being that for 25 oC the 65% of the total charge stored comes of the most accessible surfaces, and for samples to 10 oC the 52 % is originated in the surface of the most easier access. The highest capacitance value was found in the sample deposited at 10 oC. The Ƭo value was also higher, indicating that more time is needed to reach the maximum capacitance.