Rechargeable Na/Na[sub x]CoO[sub 2] and Na[sub 15]Pb[sub 4]/Na[sub x]CoO[sub 2] polymer electrolyte cells
- Univ. of California, Berkeley, CA (United States). Materials Sciences Div.
Cells using polyethylene oxide as a sodium ion conducting electrolyte, P2 phase Na[sub x]CoO[sub 2] as the positive electrode and either sodium or sodium/lead alloy as the negative electrode were assembled, discharged, and cycled. Na[sub x]CoO[sub 2] intercalates sodium over a range of x = 0.3--0.9, giving theoretical energy densities of 1,600 Wh/liter (for sodium) or 1,470 Wh/liter (for sodium/lead alloy). Cells could be discharged at rates up to 2.5 mA/cm[sup 2] corresponding to 25% depth of discharge and typically were discharged and charged at 0.5 mA/cm[sup 2] (100% depth of discharge) or approximately 1--2 C rate. Over one hundred cycles to 60% utilization or more, and two hundred shallower cycles at this rate have been obtained in this laboratory. Experimental evidence suggests that the cathode is the limiting factor in determining cycle life and not the Na/PEO interface as previously thought. Estimates of practical energy and power densities based on the cell performance and the following configuration are presented: 30--45 w/o electroactive material in the positive electrode, a twofold excess of sodium, 10 [mu]m separators, and 5 [mu]m current collectors composed of metal coated plastic. On the basis of these calculations, practical power densities of 335 W/liter for continuous discharge at 0.5 mA/cm[sup 2] and up to 2.7 kW/liter for short periods of time should be attainable. This level of performance approaches or exceeds that seen for some lithium/polymer systems under consideration for electric vehicle applications, but with a lower anticipated cost.
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 5800574
- Journal Information:
- Journal of the Electrochemical Society; (United States), Journal Name: Journal of the Electrochemical Society; (United States) Vol. 140:10; ISSN JESOAN; ISSN 0013-4651
- Country of Publication:
- United States
- Language:
- English
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250902 -- Energy Storage-- Batteries-- Performance & Testing
250903* -- Energy Storage-- Batteries-- Materials
Components
& Auxiliaries
ALKALI METAL COMPOUNDS
ALLOYS
BATTERY CHARGING
CHALCOGENIDES
COBALT COMPOUNDS
COBALT OXIDES
DATA
ELECTRIC BATTERIES
ELECTRIC-POWERED VEHICLES
ELECTROCHEMICAL CELLS
ELECTRODES
ELECTROLYTES
EXPERIMENTAL DATA
FABRICATION
INFORMATION
LEAD ALLOYS
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PERFORMANCE TESTING
POLYMERS
POWER DENSITY
SODIUM ALLOYS
SODIUM COMPOUNDS
SOLID ELECTROLYTES
TESTING
TRANSITION ELEMENT COMPOUNDS
VEHICLES