Engineering the Electronic Interaction between Atomically Dispersed Fe and RuO2 Attaining High Catalytic Activity and Durability Catalyst for Li-O2 Battery.

It is significant to develop catalysts with high catalytic activity and durability to improve the electrochemical performances of lithium-oxygen batteries (LOBs). While electronic metal-support interaction (EMSI) between metal atoms and support has shown great potential in catalytic field. Hence, to effectively improve the electrochemical performance of LOBs, atomically dispersed Fe modified RuO2 nanoparticles are designed to be loaded on hierarchical porous carbon shells (FeSA -RuO2 /HPCS) based on EMSI criterion. It is revealed that the Ru-O-Fe1 structure is formed between the atomically dispersed Fe atoms and the surrounding Ru sites through electron interaction, and this structure could act as the ultra-high activity driving force center of oxygen reduction/evolution reaction (ORR/OER). Specifically, the Ru-O-Fe1 structure enhances the reaction kinetics of ORR to a certain extent, and optimizes the morphology of discharge products by reducing the adsorption energy of catalyst for O2 and LiO2 ; while during the OER process, the Ru-O-Fe1 structure not only greatly enhances the reaction kinetics of OER, but also catalyzes the efficient decomposition of the discharge products Li2 O2 by the favorable electron transfer between the active sites and the discharge products. Hence, LOBs based on FeSA-RuO2 /HPCS cathodes show an ultra-low over-potential, high discharge capacity and superior durability.

Efficient Modulation of Electron Pathways by Constructing a MnO2-x@CeO2 Interface toward Advanced Lithium-Oxygen Batteries.

A major challenge for Li-O2 batteries is to facilely achieve the formation and decomposition of the discharge product Li2O2, and the development of an active and synergistic cathode is of great significance to efficiently accelerate its formation/decomposition kinetics. Herein, a novel strategy is presented by constructing a MnO2-x@CeO2 heterostructure on the porous carbon matrix. When it was used as a cathode for Li-O2 batteries, excellent electrochemical performances, including low overpotential, large discharge capacity, and superior cycling stability were obtained. Series theoretical calculations were conducted to reveal the mechanism for the reversible battery reactions and explain how Li2O2 interacts with the MnO2-x@CeO2 interface. Apart from the electronic ladders formed between MnO2-x 3d and CeO2 4f orbitals, which can act as a highly efficient "electron transfer expressway", the specific adsorption of MnO2-x and CeO2 with Li2O2 molecules contributes to the enhanced anchoring force of Li2O2 and delocalization of the electron cloud on the Li-O bond. Thanks to the constructed heterostructure and synergistic effect, filmlike Li2O2 can be formed through a surface pathway, and when charging, it accelerates the separation of electrons and Li+ in Li2O2, thus achieving fast redox kinetics and low overpotential.

Single-Atom Ru Implanted on Co3 O4 Nanosheets as Efficient Dual-Catalyst for Li-CO2 Batteries.

Li-CO2 battery has attracted extensive attention and research due to its super high theoretical energy density and its ability to fix greenhouse gas CO2 . However, the slow reaction kinetics during discharge/charge seriously limits its development. Hence, a simple cation exchange strategy is developed to introduce Ru atoms onto a Co3 O4 nanosheet array grown on carbon cloth (SA Ru-Co3 O4 /CC) to prepare a single atom site catalyst (SASC) and successfully used in Li-CO2 battery. Li-CO2 batteries based on SA Ru-Co3 O4 /CC cathode exhibit enhanced electrochemical performances including low overpotential, ultra high capacity, and long cycle life. Density functional theory calculations reveal that single atom Ru as the driving force center can significantly enhance the intrinsic affinity for key intermediates, thus enhancing the reaction kinetics of CO2 reduction reaction in Li-CO2 batteries, and ultimately optimizing the growth pathway of discharge products. In addition, the Bader charge analysis indicates that Ru atoms as electron-deficient centers can enhance the catalytic activity of SA Ru-Co3 O4 /CC cathode for the CO2 evolution reaction. It is believed that this work has important implications for the development of new SASCs and the design of efficient catalyst for Li-CO2 batteries.

Tailoring the components and morphology of discharge products towards highly rechargeable Li-CO/CO2 batteries.

A new non-aqueous Li-CO/CO2 battery with the main discharge products being Li2CO3 and carbon is introduced for the first time. Our findings demonstrate that with the addition of CO, the components and morphology of the discharge products are skillfully tailored, becoming more uniform, with poorer crystallinity and better conductivity. Thanks to these features, the utilization of a cathode in the Li-CO/CO2 battery system is increased and the discharge products are more easily decomposed. These positive effects caused by CO endow the Li-CO/CO2 battery with enhanced electrochemical performances.