Due to the limited energy densities,which could be achieved by lithium-ion cells,Li-O2 batteries,which could provide a promising super energy storage medium,attract much attention nowadays.For its high activity,high s...Due to the limited energy densities,which could be achieved by lithium-ion cells,Li-O2 batteries,which could provide a promising super energy storage medium,attract much attention nowadays.For its high activity,high storage and low cost,Mn-based oxides have shown versatile application in various batteries.To enhance the cyclability of Li-O2 batteries,here,we synthesized a kind of a-MnO2 nanowires as a bifunctional catalyst for Li-O2 batteries.The particular structure of a-MnO2 reduces the mass transfer resistance of the battery,and the MnO2 nanowires were ion ex-changed by saturated lithium sulfate solution so as to further improve the performance of the catalyst.The exchanged a-MnO2 catalyst showed a high discharge specific capacity(6243 mA·h/g at a current density of 200 mA/g)and signifi-cantly improved the cyclability up to the 55th cycle(200 mA/g with capacity of 1000 mA h/g).The results show that the Li ion exchange method is a promising strategy for improving the performance of MnO2 catalyst for Li-O2 batteries.展开更多
基金Supported by the National Natural Science Foundation of China(No.21606021)the Youth Scholars Program of Beiing Normal University,China(No.2014NT07).
文摘Due to the limited energy densities,which could be achieved by lithium-ion cells,Li-O2 batteries,which could provide a promising super energy storage medium,attract much attention nowadays.For its high activity,high storage and low cost,Mn-based oxides have shown versatile application in various batteries.To enhance the cyclability of Li-O2 batteries,here,we synthesized a kind of a-MnO2 nanowires as a bifunctional catalyst for Li-O2 batteries.The particular structure of a-MnO2 reduces the mass transfer resistance of the battery,and the MnO2 nanowires were ion ex-changed by saturated lithium sulfate solution so as to further improve the performance of the catalyst.The exchanged a-MnO2 catalyst showed a high discharge specific capacity(6243 mA·h/g at a current density of 200 mA/g)and signifi-cantly improved the cyclability up to the 55th cycle(200 mA/g with capacity of 1000 mA h/g).The results show that the Li ion exchange method is a promising strategy for improving the performance of MnO2 catalyst for Li-O2 batteries.
