Rechargeable aprotic lithium-oxygen (Li-O₂) batteries, owning a high theoretical energy density of , have received extraordinary attention for their potential applications in electric vehicles and energy storage.¹ However, several challenges of the lithium-oxygen batteries are still perplexing the researchers and hindering the practical applications of Li-O₂ batteries, which involve high overpotential, poor cyclic stability, weak power capability, low round-trip efficiency and so on. Hence, it is important and imperative to develop efficient cathode catalysts if a better Li-O₂battery is required

Here, we show that copper doped cobalt oxide(Cu_xCo_3-xO₄) nanoneedles as efficient catalysts in Li-O₂ batteries. This catalyst showed good catalytic activities in both ORR and OER that could reduce the recharge plateau to 3.9V versus Li/Li⁺. The synergistic effect of high electrocatalytical activity and large specific surface area ensures the improved cycle stability and enhanced capacity of Li-O₂ batteries. Furthermore, we found that the catalytical activity of this catalyst was strengthened with more proportion of doped copper, which indicated that the mingle of copper promoted the performance of cobalt oxide as cathode catalyst. This study suggests that Cu_xCo_3-xO₄ nanoneedles could be used as a competent cathode catalyst in Li-O₂ batteries, while we can control its catalytical activity by changing the amount of dopant. We expect that Cu_xCo_3-xO₄ nanoneedles are the promising candidate as the cathode catalyst to be used in practical Li-O₂batteries.

Fig. 1. (a)Discharge and charge profiles of a Li-O₂ battery containing 30% Cu_xCo_3-xO₄ in carbon matrix using TEGDME electrolyte with limited capacity of 1000 mAh/g at a constant current density of 100 mA/g; (b) Cyclability of the same cell shown in (a).

References

[1] Luntz, A. C., Bryan D. M. Chemical reviews. 2014, 114, 11721-11750.

[2] Shao Y, Park S, Xiao J, Zhang JG, Wang Y, Liu J. Acs Catalysis. 2012,2, 844-857