Lithium-silver vanadium oxide cells

Demand pacemakers are very low current devices, requiring only 25-50 jiW for sensing and 60-100 pW for stimulation. In contrast, implanted ventricular defibrillators (Fig. 1.3) must be able to deliver short electric pulses of 25-40 J (e.g. 2 A at 2 V for 10 s) which can shock the heart into normal rhythm, and hence require a much higher rate battery. The most common system is a lithium-silver vanadium oxide cell with a liquid-organic based electrolyte. More than 80 000 such units have been implanted. Implanted drug delivery devices also use lithium primary batteries, as do neurostimulators and bone growth stimulators. 

Takeuchi, E.S. and W.C. Thiebolt. 1988. The reduction of silver vanadium oxide in lithium/silver vanadium oxide cells. J. Electrochem. Soc. 135 2691-2694. 

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Root MJ (2011) Resistance model for lithium-silver vanadium oxide cells. J Electrochem Soc 158(12) A1347. doi 10.1149/2.049112jes... 

Li2S204 being the SEI component at the Li anode and the solid discharge product at the carbon cathode. The Li—SOCI2 and Li—SO2 systems have excellent operational characteristics in a temperature range from —40 to 60 °C (SOCI2) or 80 °C (SO2). Typical applications are military, security, transponder, and car electronics. Primary lithium cells have also various medical uses. The lithium—silver—vanadium oxide system finds application in heart defibrillators. The lithium—iodine system with a lithium iodide solid electrolyte is the preferred pacemaker cell. 

Explains signal transduction processes and related biology, biochemistry, and cell biology in a way that is accessible to chemists Provides detailed descriptions of vanadium batteries Describes recent advances in the applications of the lithium/silver vanadium oxide battery, particularly for medical applications... 

The earliest implantable defibrillators used lithium-vanadium oxide (LiA 205) cells. The chemical stability of this type of cell was unsatisfactory, and they were soon replaced with lithium-silver vanadium oxide (Li/Ag2V40n or Li/SVO) cells. Until only the last few years, AlAgjW4Ou cells were by far the most common cell system used in implantable defibrillators. 

Fig. 11.9 Low continuous current and high current pulse discharge voltages for a lithium-silver vanadium oxide (Li/Ag2V40n) cell...

According to cardiologists, the Li-AgVOj battery is best suited for implantable pacemaker devices. The anode of this battery is made from lithium metal and the cathode is made from silver vanadium oxide (Ag2V40jj). The cell chemical reaction is given by the following equation ... 

The use of SVO as a rechargeable cathode material is enticing due to the high-energy density (> 300 mAh/g) of this material. However, during the discharge reaction of a lithium/SVO cell, the reduced silver is replaced by lithium in the vanadium oxide matrix. Therefore, the reversibility of this lithium for silver substitution under charge conditions is still a matter of debate, as will be outlined below. 

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