Single-atom catalysts (SACs) have been applied in many fields due to their superior catalytic performance. Because of the unique properties of the single-atom-site, using the single atoms as catalysts to synthesize SACs is promising. In this work, we have successfully achieved Co SAC using Pt atoms as catalysts.
View Article and Find Full Text PDFSolid-state electrolytes (SSEs) have attracted considerable attention as an alternative for liquid electrolytes to improve safety and durability. Sodium Super Ionic CONductor (NASICON)-type SSEs, typically NaZrSiPO, have shown great promise because of their high ionic conductivity and low thermal expansivity. Doping La into the NASICON structure can further elevate the ionic conductivity by an order of magnitude to several mS/cm.
View Article and Find Full Text PDFSingle-atom catalysts (SACs) have attracted significant attention due to their superior catalytic activity and selectivity. However, the nature of active sites of SACs under realistic reaction conditions is ambiguous. In this work, high loading Pt single atoms on graphitic carbon nitride (g-C N )-derived N-doped carbon nanosheets (Pt /NCNS) is achieved through atomic layer deposition.
View Article and Find Full Text PDFSingle atomic Pt catalysts exhibit particularly high hydrogen evolution reaction (HER) activity compared to conventional nanomaterial-based catalysts. However, the enhanced mechanisms between Pt and their coordination environment are not understood in detail. Hence, a systematic study examining the different types of N in the support is essential to clearly demonstrate the relationship between Pt single atoms and N-doped support.
View Article and Find Full Text PDFConfiguring metal single-atom catalysts (SACs) with high electrocatalytic activity and stability is one efficient strategy in achieving the cost-competitive catalyst for fuel cells' applications. Herein, the atomic layer deposition (ALD) strategy for synthesis of Pt SACs on the metal-organic framework (MOF)-derived N-doped carbon (NC) is proposed. Through adjusting the ALD exposure time of the Pt precursor, the size-controlled Pt catalysts, from Pt single atoms to subclusters and nanoparticles, are prepared on MOF-NC support.
View Article and Find Full Text PDFThe Li metal anode has been long sought-after for application in Li metal batteries due to its high specific capacity (3860 mAh g ) and low electrochemical potential (-3.04 V vs the standard hydrogen electrode). Nevertheless, the behavior of Li metal in different environments has been scarcely reported.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
August 2020
Li- and Mn-rich layered oxides are among the most promising cathode materials for Li-ion batteries with high theoretical energy density. Its practical application is, however, hampered by the capacity and voltage fade after long cycling. Herein, a finite difference method for near-edge structure (FDMNES) code was combined with in situ X-ray absorption spectroscopy (XAS) and transmission electron microscopy/electron energy loss spectroscopy (TEM/EELS) to investigate the evolution of transition metals (TMs) in fresh and heavily cycled electrodes.
View Article and Find Full Text PDFAn amendment to this paper has been published and can be accessed via a link at the top of the paper.
View Article and Find Full Text PDFSingle atom catalysts exhibit particularly high catalytic activities in contrast to regular nanomaterial-based catalysts. Until recently, research has been mostly focused on single atom catalysts, and it remains a great challenge to synthesize bimetallic dimer structures. Herein, we successfully prepare high-quality one-to-one A-B bimetallic dimer structures (Pt-Ru dimers) through an atomic layer deposition (ALD) process.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
November 2019
To promote the development of solid-state batteries, polymer-, oxide-, and sulfide-based solid-state electrolytes (SSEs) have been extensively investigated. However, the disadvantages of these SSEs, such as high-temperature sintering of oxides, air instability of sulfides, and narrow electrochemical windows of polymers electrolytes, significantly hinder their practical application. Therefore, developing SSEs that have a high ionic conductivity (>10 S cm ), good air stability, wide electrochemical window, excellent electrode interface stability, low-cost mass production is required.
View Article and Find Full Text PDFAluminum foil is the predominant cathodic current collector in lithium-based batteries due to the high electronic conductivity, stable chemical/electrochemical properties, low density, and low cost. However, with the development of next-generation lithium batteries, Al current collectors face new challenges, such as the requirement of increased chemical stability at high voltage, long-cycle-life batteries with different electrolyte systems, as well as improved electronic conductivity and adhesion for new electrode materials. In this study, we demonstrate a novel graphene-like carbon (GLC) coating on the Al foil in lithium-based batteries.
View Article and Find Full Text PDFACS Appl Mater Interfaces
August 2019
As a competitive anode material for sodium-ion batteries (SIBs), a commercially available red phosphorus, featured with a high theoretical capacity (2596 mA h g) and a suitable operating voltage plateau (0.1-0.6 V), has been confronted with a severe structural instability and a rapid capacity degradation upon large volumetric change.
View Article and Find Full Text PDFLithium-sulfur (Li-S) batteries with high sulfur loading are urgently required in order to take advantage of their high theoretical energy density. Ether-based Li-S batteries involve sophisticated multistep solid-liquid-solid-solid electrochemical reaction mechanisms. Recently, studies on Li-S batteries have widely focused on the initial solid (sulfur)-liquid (soluble polysulfide)-solid (Li S ) conversion reactions, which contribute to the first 50% of the theoretical capacity of the Li-S batteries.
View Article and Find Full Text PDFThe ability to release, as electrical energy, potential energy stored at the water:carbon interface is attractive, since water is abundant and available. However, many previous reports of such energy converters rely on either flowing water or specially designed ionic aqueous solutions. These requirements restrict practical application, particularly in environments with quiescent water.
View Article and Find Full Text PDFCarbon coating is a commonly employed technique for improving the conductivity of active materials in lithium ion batteries. The carbon coating process involves pyrolysis of organic substance on lithium iron phosphate particles at elevated temperature to create a highly reducing atmosphere. This may trigger the formation of secondary phases in the active materials.
View Article and Find Full Text PDFThe development of solid-state electrolytes by atomic layer deposition (ALD) holds unparalleled advantages toward the fabrication of next-generation solid-state batteries. Lithium niobium oxide (LNO) thin films with well-controlled film thickness and composition were successfully deposited by ALD at a deposition temperature of 235 °C using lithium tert-butoxide and niobium ethoxide as Li and Nb sources, respectively. Furthermore, incorporation of higher Li content was achieved by increasing the Li-to-Nb subcycle ratio.
View Article and Find Full Text PDFA novel two-step surface modification method that includes atomic layer deposition (ALD) of TiO followed by post-annealing treatment on spinel LiNi Mn O (LNMO) cathode material is developed to optimize the performance. The performance improvement can be attributed to the formation of a TiMn O (TMO)-like spinel phase resulting from the reaction of TiO with the surface LNMO. The Ti incorporation into the tetrahedral sites helps to combat the impedance growth that stems from continuous irreversible structural transition.
View Article and Find Full Text PDFSodium-oxygen batteries have received a significant amount of research attention as a low-overpotential alternative to lithium-oxygen. However, the critical factors governing the composition and morphology of the discharge products in Na-O cells are not thoroughly understood. Here we show that oxygen containing functional groups at the air electrode surface have a substantial role in the electrochemical reaction mechanisms in Na-O cells.
View Article and Find Full Text PDFPlatinum-based catalysts have been considered the most effective electrocatalysts for the hydrogen evolution reaction in water splitting. However, platinum utilization in these electrocatalysts is extremely low, as the active sites are only located on the surface of the catalyst particles. Downsizing catalyst nanoparticles to single atoms is highly desirable to maximize their efficiency by utilizing nearly all platinum atoms.
View Article and Find Full Text PDFderived by atomic layer deposition (ALD) is used to coat the 5 V LiNiMnO cathode material powders, which dramatically increases the capacity retention of LiNiMnO. It is believed that the amorphous FePO layer could act as a lithium-ions reservoir and electrochemically active buffer layer during the charge/discharge cycling, helping achieve high capacities in LiNiMnO, especially at high current densities.
View Article and Find Full Text PDFEncapsulation of Pt nanoparticles (NPs) in a zirconia nanocage by area-selective atomic layer deposition (ALD) can significantly enhance both the Pt stability and activity. Such encapsulated Pt NPs show 10 times more stability than commercial Pt/C catalysts and an oxygen reduction reaction (ORR) activity 6.4 times greater than that of Pt/C.
View Article and Find Full Text PDFAtomic layer deposition is successfully applied to synthesize lithium iron phosphate in a layer-by-layer manner by using self-limiting surface reactions. The lithium iron phosphate exhibits high power density, excellent rate capability, and ultra-long lifetime, showing great potential for vehicular lithium batteries and 3D all-solid-state microbatteries.
View Article and Find Full Text PDFNitrogen-doped graphene nanosheets (N-GNSs) displayed a discharge capacity two times greater than their pristine counterpart, as well as superior electrocatalytic activity as a cathode material for sodium-air batteries. The enhanced performance of N-GNSs is attributed to the active sites introduced by nitrogen doping.
View Article and Find Full Text PDFBirnessite flower-like and α-type tubular MnO(2) nanostructures were selectively synthesized through simple decomposition of KMnO(4) under hydrochloric acid condition by controlling reaction temperature using a microwave-assisted hydrothermal method. The as-prepared samples were characterized in detail by various techniques including X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, Fourier transform-infrared spectroscopy, and Raman scattering spectroscopy. While the growth of flower-like birnessite-MnO(2) might follow a widely accepted Ostwald ripening process, we proposed a formation mechanism of the nanotubular α-MnO(2) based on our evidence, which was assembly of nanorods through an "oriented attachment" process.
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