PRECIOUS METAL/CARBON NANOCOMPOSITES AS CATHODE CATALYST FOR LITHIUM-AIR BATTERIES

Abstract

Rechargeable lithium air (Li–air) battery has received extensive attentions due to the high energy density. Despite of the attractive prospects, some issues still limit its development. The development of cathode catalyst has been demonstrated as an effective strategy to improve the battery performance. In this thesis, we have developed a series of precious metal/carbon nanocomposites for rechargeable Li-air battery. In our first work, Ru NPs were decorated on hierarchical carbon nanocages (hCNCs). Benefitting from the synergistic effect of hCNC sporous skeleton frame and high catalytic activity of Ru, Ru functionalized hCNCs exhibited high discharge capacity, reduced charge potential and outstanding rate performance. In our second work, Pd NPs were dispersed on graphene nanosheets (GNSs). The results indicated that Pd can promote the formation of nano-sized Li2O2. This tailored morphology provides sufficient reaction interface and enhances the surface-related transport phenomena, which is beneficial for the decomposition of Li2O2. In our third work, Ru functionalized GNSs were employed as cathode material for Li-CO2 battery. Our results indicated that Ru can promote the decomposition of Li2CO3 at a low voltage of 4.02 V, much lower than the previous reported results. Lastly, further work to optimize the precious metal/carbon nanocomposites is proposed.