The present study explored a new method to improve the catalytic activity of non-precious metals, especially in electrochemical reactions. Highly ionized Fe plasma produced by arc discharge was uniformly deposited on ...The present study explored a new method to improve the catalytic activity of non-precious metals, especially in electrochemical reactions. Highly ionized Fe plasma produced by arc discharge was uniformly deposited on a porous carbon substrate and formed atomic clusters on the carbon surface. The as-prepared FeO~/C material was tested as a cathode material in a rechargeable Li-02 battery under different current rates. The results showed significant improvement in battery performance in terms of both cycle life and reaction rate. Furthermore, X-ray diffraction （XRD） and scanning electron microscopy （SEM） results showed that the as-prepared cathode material stabilized the cathode and reduced side reactions and that the current rate was a critical factor in the nucleation of the discharge products.展开更多
The discharge and charge mechanisms of rechargeable Li-O2 batteries have been the subject of extensive investigation recently. However, they are not fully understood yet. Here we report a systematic study of the morph...The discharge and charge mechanisms of rechargeable Li-O2 batteries have been the subject of extensive investigation recently. However, they are not fully understood yet. Here we report a systematic study of the morphological transition of Li2O2 from a single crystalline structure to a toroid like particle during the discharge-charge cycle, with the help of a theoretical model to explain the evolution of the Li2O2 at different stages of this process. The model suggests that the transition starts in the first monolayer of Li2O2, and is subsequently followed by a transition from particle growth to film growth if the applied current exceeds the exchange current for the oxygen reduction reaction in a Li-O2 cell. Furthermore, a sustainable mass transport of the diffusive active species （e.g., O2 and Li＋） and evolution of the underlying interfaces are critical to dictate desirable oxygen reduction （discharge） and evolution （charge） reactions in the oorous carbon electrode of a Li-O2 cell.展开更多
文摘The present study explored a new method to improve the catalytic activity of non-precious metals, especially in electrochemical reactions. Highly ionized Fe plasma produced by arc discharge was uniformly deposited on a porous carbon substrate and formed atomic clusters on the carbon surface. The as-prepared FeO~/C material was tested as a cathode material in a rechargeable Li-02 battery under different current rates. The results showed significant improvement in battery performance in terms of both cycle life and reaction rate. Furthermore, X-ray diffraction （XRD） and scanning electron microscopy （SEM） results showed that the as-prepared cathode material stabilized the cathode and reduced side reactions and that the current rate was a critical factor in the nucleation of the discharge products.
文摘The discharge and charge mechanisms of rechargeable Li-O2 batteries have been the subject of extensive investigation recently. However, they are not fully understood yet. Here we report a systematic study of the morphological transition of Li2O2 from a single crystalline structure to a toroid like particle during the discharge-charge cycle, with the help of a theoretical model to explain the evolution of the Li2O2 at different stages of this process. The model suggests that the transition starts in the first monolayer of Li2O2, and is subsequently followed by a transition from particle growth to film growth if the applied current exceeds the exchange current for the oxygen reduction reaction in a Li-O2 cell. Furthermore, a sustainable mass transport of the diffusive active species （e.g., O2 and Li＋） and evolution of the underlying interfaces are critical to dictate desirable oxygen reduction （discharge） and evolution （charge） reactions in the oorous carbon electrode of a Li-O2 cell.
