Atomically dispersed transition metal-N4 doped graphene as a LixOy nucleation site in nonaqueous lithium-oxygen batteries. (1st August 2022)

• Record Type: Journal Article
• Authors: Wang, Yanning; Wang, Rui; Li, Yinshi
• Is Part Of: Electrochimica acta. Volume 422(2022)
• Publication Date: 2022-08-01
• Subjects: Nonaqueous lithium-oxygen batteries -- Catalytic mechanism -- TM-N4 doped graphene -- DFT calculation -- Overpotential; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2022.140554
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: Focusing on the catalytic mechanism of graphene with the atomically dispersed transition metal-N4 dispersed in nonaqueous lithium-oxygen battery, the adsorption models of key intermediates Li x O y on the TM-N4 doped graphene surface are established by density functional theory (DFT) calculations. The nucleation and decomposition processes of Li2 O2 are elucidated. Both of the charge transfer and electronic hybridization between TM-3 d and O-2 p orbitals influence the adsorption energies of key intermediates Li x O y on the TM-N4 doped graphene surface. A greater adsorption energy usually corresponds to a greater TM atomic number. The adsorption energies of LiO2, Li3 O4 and Li4 O4 are the linear functions of the adsorption energy of Li2 O2 . The initial ORR processes on the Mn-N4, Fe-N4, Co-N4 doped graphene surfaces follow the two-electron reaction pathway, while the initial ORR processes on the Ni-N4 and Cu-N4 doped graphene surfaces might follow both of the two-electron and four-electron reaction pathways. The Co-N4 doped graphene possesses the overpotentials of 0.69 V for ORR and 0.92 V for OER, showing the optimal catalytic activity.