Zhang Yu, Zhang Shuting, Ma Jie, Huang Aijian, Yuan Mengwei, Li Yufeng, Sun Genban, Chen Chen, Nan Caiyun
Beijing Key Laboratory of Energy Conversion and Storage Materials Institution, College of Chemistry, Beijing Normal University, Beijing 100875, China.
Department of Chemistry, Tsinghua University, Beijing 10084, China.
ACS Appl Mater Interfaces. 2021 Aug 25;13(33):39239-39247. doi: 10.1021/acsami.1c08720. Epub 2021 Aug 10.
Lithium oxygen (Li-O) batteries have shown great potential as new energy-storage devices due to the high theoretical energy density. However, there are still substantial problems to be solved before practical application, including large overpotential, low energy efficiency, and poor cycle life. Herein, we have successfully synthesized a RuO-CoO nanohybrid with a rich oxygen vacancy and large specific surface area. The Li-O batteries based on the RuO-CoO nanohybrid shown obviously reduced overpotential and improved circulatory property, which can cycle stably for more than 100 cycles at a current density of 200 mA g. Experimental results and density function theory calculation prove that the introduction of RuO can increase oxygen vacancy concentration of CoO and accelerate the charge transfer. Meanwhile, the hollow and porous structure leads to a large specific surface area about 104.5 m g, exposing more active sites. Due to the synergistic effect, the catalyst of the RuO-CoO nanohybrid can significantly reduce the adsorption energy of the LiO intermediate, thereby reducing the overpotential effectively.
锂氧（Li-O）电池由于具有高理论能量密度，作为新型储能装置展现出了巨大潜力。然而，在实际应用之前仍有大量问题需要解决，包括大过电位、低能量效率和较差的循环寿命。在此，我们成功合成了一种具有丰富氧空位和大比表面积的RuO-CoO纳米杂化物。基于RuO-CoO纳米杂化物的锂氧电池显示出过电位明显降低，循环性能得到改善，在200 mA g的电流密度下可稳定循环100次以上。实验结果和密度泛函理论计算证明，RuO的引入可以增加CoO的氧空位浓度并加速电荷转移。同时，中空多孔结构导致约104.5 m² g的大比表面积，暴露出更多活性位点。由于协同效应，RuO-CoO纳米杂化物催化剂可显著降低LiO中间体的吸附能，从而有效降低过电位。
