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A characteristic Raman peak is identified as the fingerprint to study the enhanced el–ph coupling in vanadium-doped WS2. Vanadium atoms cause an n- to p-type transition and make ionization scattering dominate the carrier transport process in V-WS2.

A surface engineering strategy to form a highly active Fe–Ni structure on the surfaces of Ni-based catalysts. The surface Fe is readily oxidized under OER conditions, compensating for the charges of Ni and increasing the activity of Ni active sites.

A defect-induced H2O etching method was proposed to efficiently cut single-wall carbon nanotubes (SWCNTs) controllably. Short SWCNTs are promising nanoreactors for the efficient synthesis of SWCNT-based derivatives with novel properties.

High-purity and well-graphitized single-walled carbon nanotubes (SWCNTs) with excellent physiochemical properties are ideal building blocks for the assembly of various CNT macrostructures for a wide range of applications. We report the preparation of high-quality SWCNTs on a large scale using a floating catalyst chemical vapor deposition (FCCVD) method. Under the optimum conditions, the conversion rate of the carbon source to SWCNTs reached 28.8%, and 20.4% of the metal nanoparticles were active for SWCNT growth, which are 15% and ∼400 times higher than those previously reported for FCCVD synthesis, respectively. As a result, the prepared SWCNTs have a very low residual catalyst content of ∼1.9 wt % and a high rapid oxidation temperature of 717 °C. Using these high-quality SWCNTs, we spun macroscopic SWCNT fibers by a wet-spinning process. The resulting fibers had a high electrical conductivity of 6.67 MS/m, which is 32% higher than the best value previously reported for SWCNT fibers.

Recycling spent lithium-ion batteries (LIBs) is promising for resource reuse and environmental conservation but suffers from complex processing and loss of embedded value of spent LIBs in conventional metallurgy-based recycling routes. Herein, we selected a eutectic LiI-LiOH salt with the lowest eutectic point among binary eutectic lithium salt systems to provide a Li-rich molten environment, not only offering excess lithium but benefiting ion diffusion compared with that in the solid environment. Hence, the highly degraded LiNi

Birefringence is a fundamental optical property that can induce phase retardation of polarized light. Tuning the birefringence of liquid crystals is a core technology for light manipulation in current applications in the visible and infrared spectral regions. Due to the strong absorption or instability of conventional liquid crystals in deep-ultraviolet light, tunable birefringence remains elusive in this region, notwithstanding its significance in diverse applications. Here we show a stable and birefringence-tunable deep-ultraviolet modulator based on two-dimensional hexagonal boron nitride. It has an extremely large optical anisotropy factor of 6.5 × 10

Two-dimensional (2D) transition metal chalcogenides (TMCs) are promising for nanoelectronics and energy applications. Among them, the emerging non-layered TMCs are unique due to their unsaturated dangling bonds on the surface and strong intralayer and interlayer bonding. However, the synthesis of non-layered 2D TMCs is challenging and this has made it difficult to study their structures and properties at thin thickness limit. Here, we develop a universal dual-metal precursors method to grow non-layered TMCs in which a mixture of a metal and its chloride serves as the metal source. Taking hexagonal Fe

Fabricating highly crystalline macroscopic films with extraordinary electrical and thermal conductivities from graphene sheets is essential for applications in electronics, telecommunications, and thermal management. High-temperature graphitization is the only way known to date for the crystallization of all types of carbon materials, where defects are gradually removed with increasing the temperature. However, when using graphene materials as precursors including graphene oxide, reduced graphene oxide and pristine graphene, even a long-term graphitization at 3000°C can only produce graphene films with small grain sizes and abundant structural disorders, which limit their conductivities. Here, we show that high-temperature defects substantially accelerate the grain growth and ordering of graphene films during graphitization, enabling ideal AB stacking as well as over 100, 64 and 28 times improvements in grain size, electrical and thermal conductivities, respectively, from 2000 to 3000°C. This process is realized by nitrogen doping, which retards the lattice restoration of defective graphene, retaining abundant defects such as vacancies, dislocations and grain boundaries in graphene films at high temperature. With this approach, a highly ordered crystalline graphene film similar as highly oriented pyrolytic graphite is fabricated, whose electrical and thermal conductivities (∼2.0 × 104 S cm−1; ∼1.7 × 103 W m−1 K−1) are improved by ∼6 and 2 times, respectively, compared to those of the graphene films fabricated by graphene oxide. Such graphene film also exhibits a superhigh electromagnetic interference shielding effectiveness of ∼90 dB at a thickness of 10 μm, outperforming all the synthetic materials of comparable thickness including MXene films. This work not only paves the way for the technological applications of highly conductive graphene films but also provides a general strategy to efficiently improve the synthesis and properties of other carbon materials such as graphene fibers, carbon nanotube fibers, carbon fibers, polymer-derived graphite, and highly oriented pyrolytic graphite.

Developing efficient noble-metal-free surface-enhanced Raman scattering (SERS) substrates and unveiling the underlying mechanism is crucial for ultrasensitive molecular sensing. Herein, we report a facile synthesis of mixed-dimensional heterostructures via oxygen plasma treatments of two-dimensional (2D) materials. As a proof-of-concept, 1D/2D WO3-x/WSe2 heterostructures with good controllability and reproducibility are synthesized, in which 1D WO3-x nanowire patterns are laterally arranged along the three-fold symmetric directions of 2D WSe2. The WO3-x/WSe2 heterostructures exhibited high molecular sensitivity, with a limit of detection of 5 × 10−18 M and an enhancement factor of 5.0 × 1011 for methylene blue molecules, even in mixed solutions. We associate the ultrasensitive performance to the efficient charge transfer induced by the unique structures of 1D WO3-x nanowires and the effective interlayer coupling of the heterostructures. We observed a charge transfer timescale of around 1.0 picosecond via ultrafast transient spectroscopy. Our work provides an alternative strategy for the synthesis of 1D nanostructures from 2D materials and offers insights on the role of ultrafast charge transfer mechanisms in plasmon-free SERS-based molecular sensing.

Carbon aerogels (CAs) are attractive candidates for the thermal protection of aerospace vehicles due to their excellent thermostability and thermal insulation. However, the brittleness and low mechanical strength severely limits their practical applications, and no significant breakthroughs in large CAs with a high strength have been made. We report a high-pressure-assisted polymerization method combined with ambient pressure drying to fabricate large, strong, crack-free carbon/carbon (C/C) composites with an excellent load-bearing capacity, thermal stability, and thermal insulation. The composites are comprised of an aerogel-like carbon matrix and a low carbon crystallinity fiber reinforcement, featuring overlapping nanoparticles, macro-mesopores, large particle contact necks, and strong fiber/matrix interfacial bonding. The resulting C/C composites with a medium density of 0.6 g cm

Severe shuttle effect of sulfur cathodes hinders commercial application of lithium-sulfur batteries. Current technologies for sulfur cathodes by physical confinement and chemical absorptions are not enough to solve the issues of the sulfur cathodes. Organosulfur cathodes with solid-solid conversions were proposed to fundamentally avoid shuttle effect. However, in previous reports, low sulfur content and complicated electrochemical process prevent application of organosulfur cathodes in lithium-sulfur batteries. Herein, we report new solid-solid conversion based on the organosulfur cathodes in ether-based electrolytes by developing sulfur-chain controlling strategy to obtain trisulfide polymers with high sulfur content over 76 wt%. Furthermore, reaction mechanism of sulfur-based cathodes is analyzed by constructing different sulfur chains based on the strategy. Theoretical calculations suggest polymers with disulfide bonds might exhibit new lithiation behavior, which is consistent with electrochemical results. This work demonstrates new electrochemical behavior of organosulfur cathode with solid-solid conversion and show promising application prospect of these polymers.

Developing high-performance electrocatalysts with favorable phase, surface structure and electronic structure for oxygen evolution reaction (OER) is crucial for efficient electrocatalytic water splitting. With Fe3+ ions as both dopant and morphology-controlling agent, Fe-doped NiS2 microcrystals with the exposed chemically stable {0 0 1} facets were synthesized hydrothermally for electrocatalytic OER. The initial electrocatalytic OER activation processes led to the conversion of iron-rich surface layers of the NiS2 microcrystals into Fe-doped Ni (oxy)hydroxide as the shell and the residual inner of the NiS2 microcrystals as the core. Such Fe-doped NiS2 microcrystals with the derived core/shell structure only required a small OER overpotential of 277 mV to reach an electrochemical current density of 10 mA/cm2, and showed a good stability in a more than 20 h duration test almost without overpotential increase.

The quasi-intercalation reaction mechanism in solid-state Li–SPAN batteries leads to fast reaction kinetics and small volume change.

The S-LHCE strategy with the decoupling of ion pairing and ion conduction is proposed via a freeze-drying method, which realizes the recycling of solvents used and enables solid-state lithium-metal batteries with excellent electrochemical performance.

A record-high power conversion efficiency of 17.5% is achieved for a FeCl3-functionalized GO/SWCNT/Si heterojunction solar cell due to an efficient antireflection effect and surface charge transfer doping.

A nonflammable electrolyte has been designed to enhance the interfacial stability and electrochemical kinetics for lithium metal batteries. As a result, Li||NCM811 cells show stable cycling stability at an ultrahigh cut-off voltage of 4.8 V.

Terpolymer cathode materials are synthesized by designing and tuning their active components, functional groups and carbon backbones. In an A h-scale organic lithium pouch cell, the terpolymer cathode achieves a good cycling stability and a high energy density.