No abstract

Hybrid hollow spheres with a few-layered MoS2-entrapped carbon sheath configuration have been synthesized by a one pot solvothermal method.

Yolk–mesoporous shell Si@SiO2nanohybrids with controllable shell thickness were preparedviaa facile vesicle-template method, which exhibit good cycle performance and excellent rate capabilities.

As soluble catalysts, redox mediators can reduce the high charging overpotential of lithium-oxygen batteries by providing sufficient liquid-solid interface for lithium peroxide decomposition. However, the redox mediators usually introduce undesirable reactions. In particular, the so-called “shuttle effect” leads to the loss of both the redox mediators and electrical energy efficiency. In this study, an organic compound, triethylsulfonium iodide, is found to act bifunctionally as both a redox mediator and a solid electrolyte interphase-forming agent for lithium-oxygen batteries. During charging, the organic iodide exhibits comparable lithium peroxide-oxidizing capability with inorganic iodides. Meanwhile, it in situ generates an interfacial layer on lithium anode via reductive ethyl detaching and the subsequent oxidation. This layer prevents the lithium anode from reacting with the redox mediators and allows efficient lithium-ion transfer leading to dendrite-free lithium anode. Significantly improved cycling performance has been achieved by the bifunctional organic iodide redox mediator.

Where a licence is displayed above, please note the terms and conditions of the licence govern your use of this document. When citing, please reference the published version. Take down policy While the University of Birmingham exercises care and attention in making items available there are rare occasions when an item has been uploaded in error or has been deemed to be commercially or otherwise sensitive.

Developing bifunctional electrocatalysts is the primary challenge to improve the reaction efficiency of zinc-air batteries. Lattice-strain engineering constructs high-efficiency oxygen redox catalysts by tuning the physicochemical properties of nanomaterials. However, the randomness and complexity of lattice mismatch make it difficult to effectively identify the structure-activity relationship between the strain and catalyst. Herein, a strategy of Ru triggered partial coordination environment mutation of ZnIn 2 S 4 (R 0.1 ZIS) to regulate the d-band center of catalytic sites is provided, which dramatically activates intrinsic activity and accelerates electron transfer. Density functional theory calculations and system characterizations reveal that local lattice strain causes anti-bonding orbital to occupy more electrons and narrower bandwidth, reduce the migration energy barrier of * OH deprotonation and optimize the adsorption/desorption process of oxygen-containing intermediates, thus demonstrating extraordinary catalytic performance in oxygen reduction reaction and oxygen evolution reaction. Expectedly, the R 0.1 ZIS-based cell delivers the open circuit potential of 1.587 V almost identical to the theoretical voltage, and an ultralow voltage gap of 0.71 V after undergoing 262 h operation. This work offers a promising avenue for building lattice-strain engineering to realize robust bifunctional electrocatalysts.

No abstract

Novel Si@double-shelled carbon (Si@DC) yolk-like powders have been fabricated by using the reinvented Si@void@mesoporous silica nanostructures as templates for the first time. The fabrication is quite economical without special equipment and using cheap glucose as the carbon source. In this special architecture, commercial Si nanoparticles are completely sealed inside the ultrathin and intact double-shelled carbon with rationally designed void spaces between the cores and shells, which can accommodate the volume fluctuation of Si cores. When tested as an anode material in lithium-ion batteries (LIBs), the resulting Si@DC yolk-like powders exhibit outstanding cycling stability and enhanced lithium storage capacity.Silicon is a promising alloy-type anode material for future lithium ion battery (LIBs), because of its highest known capacity (4200 mAh g −1 by forming Li 4.4 Si, more than ten times of graphite), relatively low working potential (0.2 V vs. Li/Li + ) and natural abundance.