The Reduction of Silver Vanadium Oxide in Lithium/Silver Vanadium Oxide Cells

The reduction of silver vanadium oxide (SVO, AgV₂O_5.5) cathodes by lithium was studied by chemical and electrochemical techniques. Discharge of Li-SVO cells showed that SVO can intercalate 3.5 equivalents of lithium to a 1.5V limit. Cells under low drain show voltage plateaus at 3.2, 2.8, 2.5, 2.2, and 1.8V. Voltammetry at a scan rate of 0.08 mV/s from 4.0 to 1.5V vs. lithium showed the reduction of SVO to take place in five steps at voltages of 3.3, 3.0, 2.8, 2.5, and 2.0V. Comparison with voltammetry of silver oxide and vanadium pentoxide shows that the wave at 2.8 is likely to be the reduction of Ag(I) to Ag(0). The waves at 3.3, 3.0, and 2.5V apparently are the reduction of V(V) to V(IV), while the wave at 2.0V correlates with further reduction of vanadium.