Internal Electric Field and Interfacial Bonding Engineered Step‐Scheme Junction for a Visible‐Light‐Involved Lithium–Oxygen Battery

Abstract

Li–O2 batteries have aroused considerable interest in recent years, however they are hindered by high kinetic barriers and large overvoltages at cathodes. Herein, a step‐scheme (S‐scheme) junction with hematite on carbon nitride (Fe2O3/C3N4) is designed as a bifunctional catalyst to facilitate oxygen redox for a visible‐light‐involved Li–O2 battery. The internal electric field and interfacial Fe−N bonding in the heterojunction boost the separation and directional migration of photo‐carriers to establish spatially isolated redox centers, at which the photoelectrons on C3N4 and holes on Fe2O3 remarkably accelerate the discharge and charge kinetics. These enable the Li–O2 battery with Fe2O3/C3N4 to present an elevated discharge voltage of 3.13 V under illumination, higher than the equilibrium potential 2.96 V in the dark, and a charge voltage of 3.19 V, as well as superior rate capability and cycling stability. This work will shed light on rational cathode design for metal–O2 batteries.

Promoted photocarrier separation by dipole engineering in two-dimensional perovskite/C2N van der Waals heterostructures

“…Based on the Z-scheme mechanism, a new mechanism called the step-scheme (S-scheme) has also been reported, which is applicable to several photocatalytic processes. [79][80][81] In Fig. 4(c), the band edge positions of each monolayer and Cs 3 Bi 2 I 9 /C 2 N heterostructure relative to the vacuum level are shown schematically based on HSE06 calculations at both pH = 0 and pH = 7.…”

Fabrication of an S-Scheme AgBr–PI Heterojunction for Biphenyl A Degradation and Its Degradation Pathways and Mechanism

“…30 Meanwhile, in comparison with PI, the binding energies of N 1s and C 1s in 0.5-AP shifted about 0.2−0.3 eV toward higher As the semiconductors come into contact, the electron would flow to lower E F from high E F . 31 Based on the XPS analysis the electron transfer from PI to AgBr indicates the construction of a built-in electric field (BEF) at the interface between PI and AgBr. Photocatalytic Performance and Stability.…”

“…The shift in binding energies indicates that the electron density on the sample surface has changed, owing to electron transfer between semiconductors with different Fermi energies ( E F ). As the semiconductors come into contact, the electron would flow to lower E F from high E F . Based on the XPS analysis the electron transfer from PI to AgBr indicates the construction of a built-in electric field (BEF) at the interface between PI and AgBr.…”

A long life solid-state lithium–oxygen battery enabled by a durable oxygen deficient flower-like CeO2microsphere based solid electrolyte

“…26,27 On the other hand, ceria (CeO 2 ) has been used as an inorganic filler for the preparation of a CSE due to its large number of oxygen vacancies, but the scavenging ability of CeO 2 for free radicals has been neglected by researchers. 28,29 Monodisperse flower-like CeO 2 microspheres with micro/nanostructures, high specific surface areas, and rich oxygen vacancies were successfully synthesized by a hydrothermal method in our group, which has been used for various catalytic reactions and fuel cells. [30][31][32][33][34][35][36][37] In this work, based on the excellent safety performance of the PVDF-HFP-based composite solid electrolyte and the unique scavenging ability of ceria for excess free radicals, we added 10 wt% flower-like CeO 2 microspheres (FL-CeO 2 ), together with bistrifluoromethanesulfonimide lithium salt (LiTFSI), LLZO, and PVDF-HFP to form a durable CSE.…”

“…26,27 On the other hand, ceria (CeO 2 ) has been used as an inorganic filler for the preparation of a CSE due to its large number of oxygen vacancies, but the scavenging ability of CeO 2 for free radicals has been neglected by researchers. 28,29 Monodisperse flower-like CeO 2 microspheres with micro/nanostructures, high specific surface areas, and rich oxygen vacancies were successfully synthesized by a hydrothermal method in our group, which has been used for various catalytic reactions and fuel cells. 30–37…”