Phosphorene, monolayer or few‐layer black phosphorus (BP), has recently triggered strong scientific interest for lithium/sodium ion batteries (LIBs/SIBs) applications. However, there are still challenges regarding large‐scale fabrication, poor air stability. Herein, we report the high‐yield synthesis of phosphorene with good crystallinity and tunable size distributions via liquid‐phase exfoliation of bulk BP in formamide. Afterwards, a densely packed phosphorene–graphene composite (PG‐SPS, a packing density of 0.6 g cm−3) is prepared by a simple and easily up‐scalable spark plasma sintering (SPS) process. When working as anode materials of LIBs, PG‐SPS exhibit much improved first‐cycle Coloumbic efficiency (60.2%) compared to phosphorene (11.5%) and loosely stacked phosphorene–graphene composite (34.3%), high specific capacity (1306.7 mAh g−1) and volumetric capacity (256.4 mAh cm−3), good rate capabilities (e.g., 415.0 mAh g−1 at 10 A g−1) as well as outstanding long‐term cycling life (91.9% retention after 800 cycles at 10 A g−1). Importantly, excellent air stability of PG‐SPS over the 60 days observation in maintaining its high Li storage properties can be achieved. On the contrary, 95.2% of BP in PG sample was oxidized after only 10 days exposure to ambience, leading to severe degradation of electrochemical properties.

0D transition metal phosphides (TMPs) nanocrystals (NCs)–2D ultrathin black phosphorus (BP) heterostructure (Ni2P@BP) have been synthesized via a facile sonication‐assisted exfoliation followed by a solvothermal process. Compared with the bare BP, the specially designed Ni2P@BP architecture can enhance the electrical conductivity (from 2.12 × 102 to 6.25 × 104 S m–1), tune the charge carrier concentration (from 1.25 × 1017 to 1.37 × 1020 cm–3), and reduce the thermal conductivity (from 44.5 to 7.69 W m–1 K–1) at 300 K, which can be considered for multiple applications. As a result, the Ni2P@BP exhibits excellent Li storage properties and high hydrogen evolution reaction electrocatalytic activities. The Ni2P@BP shows improved Li diffusion kinetics (e.g., the Li ions diffusion coefficient increases from 1.14 × 10–14 cm2 s–1 for pure BP nanosheets to 8.02 × 10–13 cm2 s–1 for Ni2P@BP). In addition, the Ni2P@BP electrode sustains hydrogen production with almost unchanged activity over 3000 cycles, which indicates its good chemical stability when operating under strong reducing environment.

convert waste heat into electricity. [2] The thermoelectric performance is evaluated by the dimensionless figure of merit ZT of the materials, as ZT = S 2 σT/κ, where S is the Seebeck coefficient, σ is the electrical conductivity, T is the absolute temperature, and κ is the thermal conductivity, respectively. [3] Over the past decades, substantial progress has been made in the development of high performance TE materials by adopting advanced processing techniques, [4] new material design concepts, [5] and band engineering [6] on traditional TE materials. In addition, pursuing new materials with unique micro/nanostructures [7] and/ or special crystal structures [8] also has proven successful in yielding high TE performance. [9] For practical applications, developing earth-abundant, lowcost TE materials with high ZT values is highly desired. In this regard, Pb-free Sn-based compounds such as SnSe, [10] SnTe, [11] Mg 2 Sn, [12] and TiNiSn [13] -based compounds are considered to be promising for medium temperature TE applications. Recently, the CdI 2 -type dichalcogenide semiconductor SnSe 2 has drawn a lot of interest due to its unique layered structure (Figure S1, Supporting Information), in which the intralayer Sn and Se atoms are covalently bonded in the ab planes and the layers are held together by interlayer van der Waals interactions along the c-axis. Thus SnSe 2 shows anisotropic electronic and optoelectronic properties. [14] More importantly, theoretical studies [15] have predicted that SnSe 2 could be a promising n-type TE material with a predicted high ZT value of 2.95 along the a-axis, while a lower ZT of 0.68 along the c-axis at 800 K with a carrier concertation of 10 20 cm −3 due to the anisotropic electrical and thermal transport properties. [16] This indicates that the orientation and carrier concentration are the key factors for high TE performance. However, only a few experimental studies on SnSe 2 have been reported, and the low carrier concentration (≈10 17 cm −3 ) and random-oriented grains still result in a low power factor (≈150 µW m −1 K −2 ) and ZT (≈0.2). [16b] Herein, we employ a defect chemistry approach [17] by simultaneously introducing a selenium (Se) deficiency and chlorine (Cl) doping in SnSe 2 nanoplate-based pellets, in which the nano plates show a preferable orientation of the (001) planes along the primary surface of the pellet (in-plane). This yields a sharp increase in the in-plane electrical conductivity and It is reported that electron doped n-type SnSe 2 nanoplates show promising thermoelectric performance at medium temperatures. After simultaneous introduction of Se deficiency and Cl doping, the Fermi level of SnSe 2 shifts toward the conduction band, resulting in two orders of magnitude increase in carrier concentration and a transition to degenerate transport behavior. In addition, all-scale hierarchical phonon scattering centers, such as point defects, nanograin boundaries, stacking faults, and the layered nanostructures, cooperate to produce very low lattice the...

Considerable progress has been made over the last decades in thermal spray technologies, practices and applications. However, like other technologies, they have to continuously evolve to meet new problems and market requirements. This article aims to identify the current challenges limiting the evolution of these technologies and to propose research directions and priorities to meet these challenges. It was prepared on the basis of a collection of short articles written by experts in thermal spray who were asked to present a snapshot of the current state of their specific field, give their views on current challenges faced by the field and provide some guidance as to the R&D required to meet these challenges. The article is divided in three sections that deal with the emerging thermal spray processes, coating properties and function, and biomedical, electronic, aerospace and energy generation applications.

3D SPS-synthesized, superhydrophobic and hierarchical reduced graphene oxide is exploited for high-performance NO2 detection with good immunity to humidity.

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We investigated the effect of international collaboration (in the form of international co-authorship) on the impact of publications of young universities (<50 years old), and compared to that of renowned old universities (>100 years old). The following impact indicators are used in this study, they are: (1) the 5-year citations per paper (CPP) data, (2) the international co-authorship rate, (3) the CPP differential between publications with and without international co-authorships, and (4) the difference between the percentage of international co-authored publications falling in the global top 10 % highly cited publications and the percentage of overall publications falling in the global top 10 % highly cited publications (Δ%Top10%). The increment of 5-year (2010–2014) field weighted citation impact (FWCI) of internationally co-authored papers over the 5-year overall FWCI of the institutions in SciVal® is used as another indicator to eliminate the effect of discipline difference in citation rate. The results show that, for most top institutions, the difference between the citations per paper (CPP) for their publications with and without international co-authorship is positive, with increase of up to 5.0 citations per paper over the period 1996–2003. Yet, for some Asian institutions, by attracting a lot of researchers with international background and making these collaborating “external” authors as internal researchers, these institutions have created a special kind of international collaboration that are not expressed in co-authorship, and the CPP gaps between publications with and without international co-authorship are relatively small (around 0–1 citations per paper increment) for these institutions. The top old institutions have higher CPP than young institutions, and higher annual research expenditures; while young universities have a higher relative CPP increment for the current 5-year period over the previous 5-year period. The Δ%Top10% for international co-authored publications is generally higher than that for all journal publications of the same institution. With the increase of international co-authorship ratio, the mean geographical collaboration distance (MGCD, an indication of increased international co-authorship) of one institution based on the Leiden Ranking data also increases, and young institutions have relatively higher CPP increment over MGCD increment. International co-authorship has a positive contribution to the FWCI of the institution, yet there are untapped potential to enhance the collaboration among young institutions.

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