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Transition metal oxychlorides (TMOCl) have attracted great attention as promising cathode materials for chloride ion batteries (CIBs). However, current research on TMOCl has been mainly focused on FeOCl and VOCl. On the other hand, the theoretical study of anionic rechargeable batteries faces the difficulty of predicting the discharge voltage of the electrode materials based on the half-cell system. Herein, a reliable theoretical voltage formula for CIBs is proposed based on a full-cell system with Li/LiCl as the reference anode. A high throughput screening method for TMOCl is applied among 16 transition metals. After the screening according to energetic and dynamic stability, Co is identified, which can form a new cathode material of CoOCl. Compared to FeOCl and VOCl, CoOCl has a higher discharge voltage, which is beneficial for achieving a larger energy density. The small crystal field splitting energy and exchange splitting energy of Co3+ result in higher electronic conductivity. In addition, the uniform Cl− binding environment leads to a low Cl− diffusion barrier of 0.37 eV, which is much smaller than that of VOCl (0.65 eV) and FeOCl (0.58 eV). [ABSTRACT FROM AUTHOR]

Discovering efficient and low CO selectivity non-noble heterogeneous catalysts toward formic acid (FA) dehydrogenation is vital for H2 energy systems. As a heating temperature is required to activate this reaction, the strategy of coupling a FA dehydrogenation reactor with a photothermal system possesses great potential for industrial applications. Herein, a sophisticated catalyst, a Mo1.98C1.02 porous film supported on carbon fiber paper, is demonstrated, with the advantages of a porous nanostructure, small nanoparticles and a carbon-supported structure simultaneously. The composite exhibits prominent thermal catalytic FA dehydrogenation, with a CO-free H2 generation rate of 0.79 L g−1 h−1 at 100 °C. Density functional theory calculations show that the formate route (*OCHOH → *OCOH + 1/2H2 → *OCO + 1/2H2 → CO2) is the minimum energy path for H2 and CO2 formation. Besides, a photothermal device was designed based on Bi2Te3/Cu, which can absorb and convert 1 kW m−2 irradiation into a high temperature of 240 °C, due to the high sunlight absorption, low heat conduction and low heat irradiation. Thus, a sunlight-driven thermal catalytic system was designed based on this device, with a H2 generation rate of 1.07 L g−1 h−1 under 0.25 kW m−2. This value is about two orders of magnitude faster than that of photocatalytic FA decomposition over reported non-precious photocatalysts. These results demonstrate that FA dehydrogenation can be realized under weak solar irradiation with the assistance of photothermal systems, facilitating industrial applications. [ABSTRACT FROM AUTHOR]

Chalcogenide thin films are exciting candidates for electronic applications such as spintronic devices, non-volatile memories and thermoelectric materials. To achieve such applications the understanding of their thin film growth is of paramount importance. In this work the epitaxy of exemplary chalcogenides Sb2Te3 and GeTe on different surfaces of Si(111) with atomically sharp interfaces is presented and compared using plan-view transmission electron microscopy and electron diffraction. It is shown that depending on the monolayer surface termination the resulting films present drastic differences in terms of film morphology and crystallinity. In particular, a profound difference is found between the films grown on H-passivated and Sb-passivated surfaces. In both cases, the out-of-plane texture is strongly c-axis oriented, but the case of Si(111)–H shows the frequent occurrence of random in-plane twist for both films, while for Si(111)–Sb this is strongly suppressed. The role of the substrate-film interface for the epitaxy is discussed and the consequences for the properties of the films are highlighted. In general, the insights of these results shed light on chalcogenide thin film growth for topological insulator, ferroelectric, thermoelectric and phase-change materials research. [ABSTRACT FROM AUTHOR]

GeTe is a rather unconventional and complex compound from a fundamental point of view considering its very simple stoichiometry. Within this review, we first discuss the crystal structure of GeTe, focusing our attention on the bonding mechanism and on the distortion of the unit cell. This distortion is responsible for the ferroelectric properties of GeTe that are also considered here. Furthermore, we describe the amorphous phase and review the phase change material properties resorting to examples from several GeTe based alloys. Finally we examine the usage of GeTe for spintronics, a fairly recent application field. [ABSTRACT FROM AUTHOR]

A novel α-Fe2O3/graphene composite is prepared by a simple in situ wet chemistry approach. The α-Fe2O3 particles with diameter around 130 nm are homogeneously anchored on graphene nanosheets to form a 3D quasi-laminated architecture. Such a well-organized flexible structure can offer sufficient void space to facilitate the electrolyte penetration, alleviate the effect of the volume change of α-Fe2O3 particles and avoid particle–particle aggregation during lithium insertion/desertion. In addition, graphene not only improves the electric conductivity of the composite electrode but also maintains the structural integrity of the composite electrode during long-term cycling. As anode material for Li-ion batteries, the α-Fe2O3/graphene composite electrode exhibits a stable capacity of 742 mAh g−1 up to 50 cycles. The synthesis technique is suitable for practical large-scale production of graphene-based metal oxide composites as advanced electrode materials for rechargeable Li-ion batteries. [ABSTRACT FROM AUTHOR]

Olivine-structured LiMnPO(4) with 3D foldaway-lantern-like hierarchical structures have been prepared via a one-step, template-free, solvothermal approach in ethylene glycol. The foldaway-lantern-like LiMnPO(4) microstructures are composed of numerous nanoplates with thickness of about 20 nm. A series of electron microscopy characterization results indicate that the obtained primary LiMnPO(4) nanoplates are single crystalline in nature, growing along the [010] direction in the (100) plane. Time-dependent morphology evolution suggests that ethylene glycol plays dual roles in oriented growth and self-assembly of such unique structures. After carbon coating, the as-prepared LiMnPO(4) cathode demonstrated a flat potential at 4.1 V versus Li/Li(+) with a specific capacity close to 130 mA h g(-1) at 0.1 C, along with excellent cycling stability.