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Sodium-ion batteries (SIBs) suffer from limited ion diffusion and structural expansion, generating the urgent demand for Na+accommodable materials with promising architectures. In this work, the rational exploration for Co4S3nanoparticles confined in an MnS nanorod-grafted N, S-codoped carbon polyhedron (Co–Mn–S@N–S–C) is achieved by the in situ growth of MOF on MnO2nanorod along with the subsequent carbonization and sulfurization. Benefiting from the distinctive nanostructure, the Co–Mn–S@N–S–C anode delivers excellent structural stability, resulting in prolonged cycling stability with a capacity retention of 90.2% after 1000 cycles at 2 A g–1. Moreover, the reaction storage mechanism is clarified by the in situ X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements. The results indicate that properly designed electrode materials have huge potential applications for highly efficient energy storage devices.

Lead halide perovskites have shown great potential in photovoltaic and photocatalytic fields. However, the toxicity of lead impedes their wide application. Herein composites of lead-free halide perovskite Cs2AgBiBr6supported on nitrogen-doped carbon (N-C) materials were synthesized successfully through a facile one-pot method for the first time. Without deposition of noble metals as the cocatalyst, the optimal composite Cs2AgBiBr6/N-C (Cs2AgBiBr6/N-C-140) exhibits outstanding photocatalytic performance with a high hydrogen evolution rate of 380 μmol g–1h–1under visible light irradiation (λ ≥ 420 nm), which is about 19 times faster than that of pure Cs2AgBiBr6and 4 times faster than that of physically mixed Cs2AgBiBr6/N-C-140, respectively. The Cs2AgBiBr6/N-C-140 composite also displays high stability with no significant decrease after six cycles of repeated hydrogen evolution experiments. The addition of N-C with a high surface area helps to prevent aggregation of Cs2AgBiBr6NPs and provides more pathways for the migration of photoinduced carriers. The nitrogen dopant can facilitate photoinduced electron transfer from Cs2AgBiBr6to N-C to result in spatially separated electrons and holes with prolonged electron time and greatly enhance the photocatalytic performance. This study indicates that Cs2AgBiBr6-based perovskite materials are promising candidates for photocatalytic hydrogen evolution.

Flexible manipulation of the carrier transport behaviors in two-dimensional materials determines their values of practical application in logic circuits. Here, we demonstrated the carrier-type manipulation in field-effect transistors (FETs) containing α-phase molybdenum ditelluride (MoTe2) by a rapid thermal annealing (RTA) process in dry air for hole-dominated and electron-beam (EB) treatment for electron-dominated FETs. EB treatment induced a distinct shift of the transfer curve by around 135 V compared with that of the FET-processed RTA treatment, indicating that the carrier density of the EB-treated FET was enhanced by about 1 order of magnitude. X-ray photoelectron spectroscopy analysis revealed that the atomic ratio of Te decreased from 66.4 to 60.8% in the MoTe2channel after EB treatment. The Fermi level is pinned near the new energy level resulting from the Te vacancies produced by the EB process, leading to the electron-dominant effect of the MoTe2FET. The electron-dominated MoTe2FET showed excellent stability for more than 700 days. Thus, we not only realized the reversible modulation of carrier-type in layered MoTe2FETs but also demonstrated MoTe2channels with desirable performance, including long-term stability.

Extrinsically controlling the intrinsic activity and stability of two-dimensional (2D) semiconducting materials by substitutional doping is crucial for energy-related applications. However, an in situ transition-metal doping strategy for uniform and large-area chemical vapor deposited 2D semiconductors remains a formidable challenge. Here, we successfully synthesize highly uniform niobium-substituted tungsten disulfide (Nb-WS2) monolayers, with a doping concentration of nearly 7% and sizes reaching 100 μm, through a metal dopant precursor route, using salt-catalyzed chemical vapor deposition (CVD). Our results reveal unusual effects in the structural, optical, electronic, and electrocatalysis characteristics of the Nb-WS2monolayer. The Nb dopants readily induce a band restructuring effect, providing the most active site with a hydrogen adsorption energy of 0.175 eV and hence greatly improving its hydrogen evolution activity.The combined advantages of the unusual physics and chemistry by in situ CVD doping technique open the possibility in designing 2D-material-based electronics and catalysts of novel functionalities.

Chloride-ion battery is considered as the promising electrochemical system due to its high energy density in theory. However, aqueous chloride-ion redox materials are limitedly reported owing to their instability or dissolution in aqueous electrolyte. Here, we synthetize a new electrochemical chloride-ion material, Sb4O5Cl2, investigate its electrochemical performance in aqueous NaCl electrolyte, and assemble into aqueous chloride-ion battery with silver as cathode. During the battery charge process, Sb4O5Cl2anode electrochemically releases chloride ions, which are captured by Ag cathode with the formation of silver chloride while the discharging reverses the process. The battery demonstrates favorable electrochemical performance. With current density of 600 mA g–1, the battery discharge capacity of 34.6 mAh g–1can be maintained for 50 cycles. This work is greatly significant for the development of anion electrochemical energy storage.

Spinel oxides have attracted widespread interest for electrocatalytic applications owing to their unique crystal structure and properties. The surface structure of spinel oxides significantly influences the electrocatalytic performance of spinel oxides. Herein, we report a Li reduction strategy that can quickly tune the surface structure of CoFe2O4(CFO) nanoparticles and optimize its electrocatalytic oxygen evolution reaction (OER) performance. Results show that a large number of defective domains have been successfully introduced at the surface of CFO nanopowders after Li reduction treatment. The defective CFO nanoparticles demonstrate significantly improved electrocatalytic OER activity. The OER potential observed a negative shift from 1.605 to 1.513 V at 10 mA cm–2, whereas the Tafel slope is greatly decreased to 42.1 mV dec–1after 4 wt % Li reduction treatment. This efficient Li reduction strategy can also be applied to engineer the surface defect structure of other material systems and broaden their applications.