We report a facile strategy to synthesize the nanocomposite of Co3O4 nanoparticles anchored on conducting graphene as an advanced anode material for high-performance lithium-ion batteries. The Co3O4 nanoparticles obtained are 10−30 nm in size and homogeneously anchor on graphene sheets as spacers to keep the neighboring sheets separated. This Co3O4/graphene nanocomposite displays superior Li-battery performance with large reversible capacity, excellent cyclic performance, and good rate capability, highlighting the importance of the anchoring of nanoparticles on graphene sheets for maximum utilization of electrochemically active Co3O4 nanoparticles and graphene for energy storage applications in high-performance lithium-ion batteries.

We developed two-step solution-phase reactions to form hybrid materials of Mn 3 O 4 nanoparticles on reduced graphene oxide (RGO) sheets for lithium ion battery applications. Mn 3 O 4 nanoparticles grown selectively on RGO sheets over free particle growth in solution allowed for the electrically insulating Mn 3 O 4 nanoparticles wired up to a current collector through the underlying conducting graphene network. The Mn 3 O 4 nanoparticles formed on RGO show a high specific capacity up to ~900mAh/g near its theoretical capacity with good rate capability and cycling stability, owing to the intimate interactions between the graphene substrates and the Mn 3 O 4 nanoparticles grown atop. The Mn 3 O 4 /RGO hybrid could be a promising candidate material for high-capacity, low-cost, and environmentally friendly anode for lithium ion batteries. Our growth-on-graphene approach should offer a new technique for design and synthesis of battery electrodes based on highly insulating materials.

Flexible electrochemical energy storage (FEES) devices have received great attention as a promising power source for the emerging field of flexible and wearable electronic devices. Carbon nanotubes (CNTs) and graphene have many excellent properties that make them ideally suited for use in FEES devices. A brief definition of FEES devices is provided, followed by a detailed overview of various structural models for achieving different FEES devices. The latest research developments on the use of CNTs and graphene in FEES devices are summarized. Finally, future prospects and important research directions in the areas of CNT- and graphene-based flexible electrode synthesis and device integration are discussed.

Self-trapped excitons (STEs) in metal halide materials are attracting an increasing level of interest due to their unique light emission properties. Light emission from STEs in metal halides is usually associated with excited-state structural deformation, which lowers the symmetry of local structures, as seen for the STEs in a wide range of materials systems. Here, we reveal a prototypic STE-associated structural “distortion” that, however, enhances the symmetry of local structures, in a series of all-inorganic copper­(I)-based halides Cs3Cu2X5 (X = Cl, Br, or I). We further find that the emission peaks of Cs3Cu2X5 blue-shift when the halogen changes from Cl to Br to I, which is the opposite of the trends found in traditional halide perovskites. This phenomenon is attributed to a synergetic combination of the significant change in band gap associated with structural deformation and a strong excitonic effect. Due to the highly localized electron and hole upon photoexcitation, Cs3Cu2Cl5 shows an extremely long and temperature-sensitive photoluminescence (PL) lifetime among metal halide materials with STEs. Remarkably, strong green emission with a PL quantum yield exceeding 90% is found in Cs3Cu2Cl5, opening the way to designing light emission compounds based on local symmetry-enhancing STE mechanisms.

Structurally ordered intermetallic phases have exhibited higher and higher electrocatalytic activity and stability than disordered alloys in many reactions such as the oxygen reduction reaction (ORR) and small-molecule (hydrogen, formic acid, or ethanol) oxidation reactions. The enhanced electrocatalytic activity could be derived from the definite composition and predictable control over structural, geometric, and electronic effects. This review, based on the understanding of the catalytic mechanism of structurally ordered intermetallic nanoparticles, provides a comprehensive acknowledgment of how the particle size and morphology affect the catalytic performance. The strategy for reducing particle size and the impact of particle size on electrocatalysis will be first introduced. Then, recent developments in the synthesis and design of morphology-controlled catalysts are summarized. The structure−activity relationship between the catalytic activity and morphology including core−shell/hollow and porosity will be highlighted. Finally, the current challenges and future developments are provided. On the basis of this review, intermetallic nanoparticles will shed light on the future development of electrocatalysts for fuel cells and metal-air batteries.

Stringed “tube on cube” hybrid architecture is developed for high-energy-density lithium–sulfur batteries with high sulfur loading and lean electrolyte.

No abstract

progress in battery technology has been primarily driven by the specific demands of various applications. In the current era, a higher gravimetric/volumetric energy density is still an ever-growing requirement to power mobile electronics and extend the driving range of electric vehicles (EVs) with increased energy consumption. Meanwhile, the exploration and utilization of the various forms of renewable energy, such as wind, tidal, and solar energy, which are normally harvested as electricity but fluctuate greatly over time, require them to be stored, regulated, and then delivered for practical application. [1,2] As a result, these two issues impose high urgency and great necessity on the development of suitable battery systems to meet these demands, in particular, energy density, safety, and cost effectiveness. [3][4][5] At this stage, the most successfully commercialized secondary batteries are the LIBs, which have been widely applied in a variety of devices, including mobile phones, power tools, and electric vehicles. In an LIB, electricity is stored and released based on the reversible insertion-extraction of Li ions in the electrode materials. [6] The second-generation LIBs, which are based on layered LiNi x Mn y Co z O 2 (NMC) or LiNi 0.8 Co 0.15 Al 0.05 O 2 (NCA) cathode materials and graphite anode materials, normally have practical gravimetric/volumetric energy densities as high as 180-220 Wh kg −1 and have been applied in the latest electric vehicles (e.g., the Tesla Model S car) (Figure 1). Present mobile devices, transportation tools, and renewable energy technologies are more dependent on newly developed battery chemistries than ever before. Intrinsic properties, such as safety, high energy density, and cheapness, are the main objectives of rechargeable batteries that have driven their overall technological progress over the past several decades. Unfortunately, it is extremely hard to achieve all these merits simultaneously at present. Alternatively, exploration of the most suitable batteries to meet the specific requirements of an individual application tends to be a more reasonable and easier choice now and in the near future. Based on this concept, here, a range of promising alternatives to lithium-sulfur batteries that are constructed with non-Li metal anodes (e.g., Na, K, Mg, Ca, and Al) and sulfur cathodes are discussed. The systems governed by these new chemistries offer high versatility in meeting the specific requirements of various applications, which is directly linked with the broad choice in battery chemistries, materials, and systems. Herein, the operating principles, materials, and remaining issues for each targeted battery characteristics are comprehensively reviewed. By doing so, it is hoped that their design strategies are illustrated and light is shed on the future exploration of new metal-sulfur batteries and advanced materials. Metal-Sulfur BatteriesThe ORCID identification number(s) for the author(s) of this article can be found under https://doi.