Amorphous and nanocrystalline oxide electrodes for rechargeable lithium batteries
Oxo ions (MO{sub 4}){sup n-} (M = V, Cr, Mn and Mo) have been reduced in aqueous solutions with potassium borohydride to obtain the binary oxides MO{sub 2+{delta}}. While the vanadium and manganese oxides are nanocrystalline, the chromium and molybdenum oxides are amorphous. The nanocrystalline VO{sub 2} having a metastable structure and the amorphous CrO{sub 2} and MoO{sub 2.3} transform to the thermodynamically more stable phases upon heating above 300--400 C. These metastable oxides after heating in vacuum at 200--300 C to remove water show good electrode performance in lithium cells. VO{sub 2}, CrO{sub 2} and MoO{sub 2.3} show a reversible capacity of, respectively, 290 mAh/g in the range 4--1.5 V, 180 mAh/g in the range 3.3--2.3 V, and 220 mAh/g in the range 3--1 V. MnO{sub 2} obtained by this process does not show good electrode properties.
- Research Organization:
- Univ. of Texas, Austin, TX (US)
- Sponsoring Organization:
- Welch Foundation; National Science Foundation
- OSTI ID:
- 20019175
- Country of Publication:
- United States
- Language:
- English
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