title: Tuning the Morphology and Crystal Structure of Li2O2: A Graphene Model Electrode Study for Li-O2 Battery.
abstract: The performance and the cyclability of the Li-O2 batteries are strongly affected by the morphology and crystal structure of Li2O2 produced during discharge. In order to explore the details of growth and electrochemical decomposition of Li2O2, and its relationship with the cell performance, graphene films were used as model carbon electrodes and compared with electrodeposited Pd nanoparticles (NPs) on graphene. Multiple methods, including transmission/scanning electron microscopy (TEM/SEM), Raman spectroscopy, electrochemical impedance spectroscopy (EIS), and coin cell charge/discharge test, were employed for material characterization and reaction monitoring. The results showed that the presence of Pd NPs significantly changed the growth, morphology, and crystal structure of Li2O2 and reduced the charge overpotential by 1060 mV. All of these changes are ascribed to the stronger binding energy between LiO2 and the Pd surface, resulting in the generation of amorphous Li2O2 with higher ionic conductivity of Li(+) and O2(2-), which in turn improve the cell charging performance.
authors.affiliation: College of Chemistry and Molecular Sciences, Hubei Key Lab of Electrochemical Power Sources, Wuhan University , Wuhan 430072, China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Yang
authors.affiliation: College of Chemistry and Molecular Sciences, Hubei Key Lab of Electrochemical Power Sources, Wuhan University , Wuhan 430072, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Zhang
authors.affiliation: College of Chemistry and Molecular Sciences, Hubei Key Lab of Electrochemical Power Sources, Wuhan University , Wuhan 430072, China.
authors.forename: Xiaochen
authors.initials: X
authors.lastname: Wang
authors.affiliation: College of Chemistry and Molecular Sciences, Hubei Key Lab of Electrochemical Power Sources, Wuhan University , Wuhan 430072, China.
authors.forename: Linfeng
authors.initials: L
authors.lastname: Chen
authors.affiliation: College of Chemistry and Molecular Sciences, Hubei Key Lab of Electrochemical Power Sources, Wuhan University , Wuhan 430072, China.
authors.forename: Nian
authors.initials: N
authors.lastname: Wu
authors.affiliation: College of Chemistry and Molecular Sciences, Hubei Key Lab of Electrochemical Power Sources, Wuhan University , Wuhan 430072, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.affiliation: College of Chemistry and Molecular Sciences, Hubei Key Lab of Electrochemical Power Sources, Wuhan University , Wuhan 430072, China.
authors.forename: Hanlin
authors.initials: H
authors.lastname: Lu
authors.affiliation: College of Chemistry and Molecular Sciences, Hubei Key Lab of Electrochemical Power Sources, Wuhan University , Wuhan 430072, China.
authors.forename: Li
authors.initials: L
authors.lastname: Xiao
authors.affiliation: College of Chemistry and Molecular Sciences, Hubei Key Lab of Electrochemical Power Sources, Wuhan University , Wuhan 430072, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Fu
authors.affiliation: College of Chemistry and Molecular Sciences, Hubei Key Lab of Electrochemical Power Sources, Wuhan University , Wuhan 430072, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Zhuang
keywords: Li2O2 morphology; Li−O2 battery; adsorption energy of LiO2; amorphous; crystalline; electrocatalysis; graphene film; overpotential