Growth and electrochemical characterization of single phase Mo{sub x}N films for fabrication of hybrid double layer capacitors
The electrochemical stability and capacitance in H{sub 2}SO{sub 4}, KOH, and propylene carbonate of single phase polycrystalline {gamma}-Mo{sub 2}N and {delta}-MoN thin film electrodes deposited at 350 and 700 C, respectively, at a rate of 0.5 {micro}m/min on Ti substrates have been determined. The films were prepared by chemical vapor deposition at 100 torr using Mo(CO){sub 6} and NH{sub 3} flowing at 1.5 standard liters per minute (slm). Cyclic voltammetry referenced to a standard Ag/AgCl electrode indicated that both phases possessed a more positive voltage stability limit in H{sub 2}SO{sub 4} than KOH. Films of {gamma}-Mo{sub 2}N had voltage stability ranges of {minus}0.3 to 0.6 V and {minus}1.3 to {minus}0.3 V in 4.4 M H{sub 2}SO{sub 4} and 7.6 M KOH, respectively. Films of {delta}-MoN possessed voltage stability ranges of {minus}0.3 to 0.7 V and {minus}1.3 to {minus}0.3 V in the same respective electrolytes. Both phases had a voltage stability of approximately one volt in the propylene carbonate electrolyte. These results were used to design and fabricate a hybrid capacitor composed of a Ta/Ta{sub 2}O{sub 5} anode and a {delta}-MoN cathode contained in an electrolyte of 4.4 M H{sub 2}SO{sub 4}. The hybrid device had an operating voltage range between 0 and 50 V, a temperature range of {minus}55 to +90 C, a capacitance of {approx}5.0 mF and an energy density of {approx}1.32 J/cm{sup 3}. This device is now in pre-production at Evans Capacitor Corporation.
- Research Organization:
- North Carolina State Univ., Raleigh, NC (US)
- Sponsoring Organization:
- US Department of the Air Force; US Department of the Navy, Office of Naval Research (ONR)
- OSTI ID:
- 20019200
- Resource Relation:
- Conference: 1997 Materials Research Society Fall Meeting, Boston, MA (US), 12/01/1997--12/05/1997; Other Information: PBD: 1998; Related Information: In: Materials for electrochemical energy storage and conversion II -- Batteries, capacitors and fuel cells. Materials Research Society symposium proceedings, Volume 496, by Ginley, D.S.; Doughty, D.H.; Scrosati, B.; Takamura, T.; Zhang, Z.J. [eds.], 702 pages.
- Country of Publication:
- United States
- Language:
- English
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