Hybrid Ag2VO2PO4/CFx as a High Capacity and Energy Cathode for Primary Batteries

Abstract

In this report, we describe the electrochemistry of hybrid dual silver vanadium phosphorus oxide/carbon fluoride (Ag2VO2PO4/CFx) cathodes with various weight ratios. Through modification of the Ag2VO2PO4/CFx ratio, we can control the gravimetric and volumetric capacity, as well as mitigate the voltage drop during high current pulses. The increase in impedance caused by irreversible LiF formation in CFx was reduced by the silver reduction-displacement during electrochemical discharge of the Ag2VO2PO4. Moreover, the addition of graphite was shown to reduce initial voltage delay. When Ag2VO2PO4 dominates the electrode mass (i.e. 75/25 Ag2VO2PO4/CFx) in the hybrid cathode, pulse testing shows less voltage drop and delay, but at the expense of capacity and energy density. As the amount of CFx in the composite increases (i.e. Ag2VO2PO4/CFx ratio of to 50/50 or 25/75), charge capacity and energy density increases, but at the expense of larger voltage drops and delays early in the discharge process. Thus, controlling the Ag2VO2PO4/CFx ratio can be used to tune the electrochemical properties of the dual cathode, allowing for optimization of capacity and power depending on the application.