| Autor: |
Snook, Graeme A., Duffy, Noel W., Pandolfo, Anthony G. |
| Zdroj: |
ECS Transactions; February 2007, Vol. 2 Issue: 27 |
| Abstrakt: |
The effect of high current (>10C) cycling on the capacity of nickel hydroxide was investigated in aqueous KOH with the objective of increasing cycle life at high currents. Capacity loss at high voltages has been attributed to excess oxygen evolution which occurs when charging is conducted at high rates without voltage limits. Cyclic voltammetry of nickel hydroxide microparticles, attached to glassy carbon electrodes, enabled the separation of the oxidation process from oxygen evolution. With large pasted electrodes, due to their large uncompensated resistance (Ru), these processes are poorly resolved. An alternate method for the discrimination of oxygen evolution has been developed using Scanning Electrochemical Microscopy (SECM) to map the evolution of oxygen against potential. With no control of upper voltage, poor cycle-life was confirmed at 15C (40% capacity loss in 50 cycles). By contrast, voltage control based on SECM studies (Vmax = 1.45V) allowed thousands of cycles with little capacity loss. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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