关键词: 钒酸银, 银纳米颗粒, 锂一次电池, 锂氧电池, 循环利用, 氧还原/氧析出

Recycling use is one of the energy and resource saving strategies to dispose depleted batteries, especially primary lithium batteries that employ electrode materials based on expensive and low-abundance elements. In this study, we report in detail the recycling use of discharged Li-AgVO₃ primary battery for rechargeable Li-O₂ battery. We demonstrate that the discharged Li-AgVO₃ cell, in which metallic silver nanoparticles in-situ generated in the vanadium oxide nanowires cathode efficiently catalyze the oxygen reduction/evolution reactions (ORR/OER), can be resumed as rechargeable Li-O₂ cells when they are exposed at O₂ atmosphere. By controlling the discharge depths, we obtained different cathodes that were composed of vanadium oxide nanowires and silver nanoparticles. As the electrode was discharged to a lower voltage, more silver nanoparticles with larger particle size were distributed on the surface of vanadium oxides, as a result of the sequential reduction of Ag⁺ to Ag⁰ and V⁵⁺ to V⁴⁺. Specifically, the average size of formed Ag nanoparticles was 15 nm and 70 nm at ceased discharge voltage of 2.9 V and 2.0 V, respectively, while the formation of V⁴⁺ was observed at discharge voltage lower than 2.3 V. Electrochemical tests indicated that the Li-O₂ cells assembled with the AgVO₃ cathode discharged to 2.3 V (AgVO₃-2.3) exhibited the highest specific capacity (9000 mAh·g_carbon^-1), the lowest overpotential and robust cycling performance (up to 95 cycles at the current density of 300 mA·g_carbon^-1). The remarkable electrochemical performance of the Li-O₂ battery with the AgVO₃-2.3 cathode is attributed to the optimization of amount, size and distribution of generated silver nanoparticles that contribute to high electronic conductivity and abundant active sites for the ORR/OER. A combined analysis of electrochemical impedance spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy confirmed that the AgVO₃-2.3 cathode enables the reversible formation and decomposition of Li₂O₂ with lower charge transfer resistance on discharge and charge. The results presented here would provide new insight into the promising recycling application of depleted primary Li-AgVO₃ batteries in rechargeable high-capacity Li-O₂ batteries.

Key words: silver vanadium oxide, silver nanoparticles, lithium primary battery, Li-oxygen battery, recycling use, oxygen reduction/evolution