Phosphor-Doped Carbon Network Electrocatalyst Enables Accelerated Redox Kinetics of Polysulfides for Sodium-Sulfur Batteries.

Lithium-ion batteries, which have dominated large-scale energy storage for the past three decades, face limitations in energy density and cost. Sulfur, with its impressive capacity of 1675 mAh g-1 and high theoretical energy density of 1274 Wh kg-1, stands out as a promising cathode material, leading to a growing focus on sodium-sulfur (Na-S) batteries as an alternative to address lithium resource scarcity. Nevertheless, the development is restrained by poor conductivity, volume expansion of the sulfur cathode, and the shuttle effect of sodium polysulfides (Na2Sn) in the electrolytes. In this study, a facile method is designed to fabricate phosphor-doped carbon (phos-C), which is then used as a sulfur matrix. This micromesoporous phos-C network enhances sulfur utilization, increases overall cathode conductivity, and effectively mitigates the shuttling of Na2Sn. During the discharge process, phos-C can absorb soluble Na2Sn and increase the conductivity of sulfur, while serving as a reservoir for electrolyte and Na2Sn, thereby preventing their infiltration into the anode and reducing the loss of sodium. As a result, the well-designed sulfur-loaded phos-C (S/phos-C) cathode, employed in the Na-S battery, demonstrates a capacity of 1034 mAh g-1 at 0.1 C (1 C = 1675 mA g-1) and an excellent rate capability of 339 mAh g-1 at 10 C, coupled with a prolonged cycling life up to 2000 cycles at 1 C, exhibiting an ultralow capacity decay rate of 0.013% per cycle. Overall, this study introduces an efficient method for creating long-lasting Na-S batteries.

Quasi-waffle solar distiller for durable desalination of seawater.

Water purification via interfacial solar steam generation exhibits promising potential. However, salt crystallization on evaporators reduces solar absorption and obstructs water supply. To address it, a waffle-shaped solar evaporator (WSE) has been designed. WSE is fabricated via a zinc-assisted pyrolysis route, combining low-cost biomass carbon sources, recyclable zinc, and die-stamping process. This route enables cost-effective production without the need of sophisticated processing. As compared to conventional plane-shaped evaporators, WSE is featured by extra sidewalls for triggering the convection with the synergistic solute and thermal Marangoni effects. Consequently, WSE achieves spontaneous salt rejection and durable evaporation stability. It has demonstrated continuous operation for more than 60 days in brine without fouling.

Coupling MoS2 nanosheets with CeO2 for efficient electrocatalytic hydrogen evolution at large current densities.

We developed an efficient MoS2 nanosheet electrode coupled with CeO2via a hydrothermal process to facilitate water adsorption and dissociation, which displayed good HER activity and stability at a large current density of 500 mA cm-2. In situ Raman spectroscopy confirmed the formation of hydroxide ions based on the strengthening of the Ce-O bond during the HER.

A modified "gel-blowing" strategy toward the one-step mass production of a 3D N-doped carbon nanosheet@carbon nanotube hybrid network for supercapacitors.

In this work, we have realized the synchronous and large-scale synthesis of one-dimensional (1D) carbon nanotubes (CNTs) on two-dimensional (2D) N-doped carbon nanosheets (NCNS) by a one-step annealing of a Ni-containing gel precursor. Upon heating, the gel is "blown" into large-sized 2D NCNS with uniformly embedded Ni nanoparticles that can catalyze the in situ CNT growth, forming a three-dimensional (3D) N-doped carbon nanosheet@carbon nanotube (NCNS@CNT) hybrid. Different from our previous "gel-blowing" strategy for 2D nanosheets, the modified "gel-blowing" strategy is capable of producing 3D architecture by employing a new complexing agent and introducing ethanol as a carbon source. Importantly, this method can be easily scaled up by annealing more gel precursors with an increased amount of ethanol. The introduction of CNTs endows NCNS@CNTs with higher quality and larger specific surface area (SSA) than pure NCNS. Consequently, the electrochemical performance of 3D NCNS@CNTs is much superior to that of 2D NCNS and found to be related with the annealing temperature. The optimized NCNS@CNTs can deliver a specific capacitance of 124 F g-1 at 1 A g-1 and maintain 88% of their initial value after 10 000 cycles at 1 A g-1. Furthermore, NiO nanosheets are deposited on the NCNS@CNT framework to study its function as a conductive host. The as-fabricated hybrid electrode exhibits a high specific capacitance of 660 F g-1 at 1 A g-1 and 532 F g-1 at 20 A g-1, which is also better than its counterpart using NCNS as substrates. This method provides a simplified and low-cost way towards the mass production of NCNS@CNTs for energy application and beyond.

Mass Production of Large-Sized, Nonlayered 2D Nanosheets: Their Directed Synthesis by a Rapid "Gel-Blowing" Strategy, and Applications in Li/Na Storage and Catalysis.

2D nanomaterials are well suited for energy conversion and storage because of their thickness-dependent physical and chemical properties. However, current synthetic methods for translating 2D materials from the laboratory to industry cannot integrate both advantages of liquid-phase method (i.e., solution processibility, homogeneity, and massive production), and gas-phase method (i.e., high quality and large lateral size). Here, inspired by Chinese Sugar Figure Blowing Art, a rapid "gel-blowing" strategy is proposed for the mass production of 2D nonlayered nanosheets by thermally expanding the viscous gel precursors within a short time (≈1 min). A wide variety of 2D nanosheets including oxides, carbon, oxides/carbon and metal/carbon composites are synthesized on a large scale and with no impurities. Importantly, this method unifies the merits of both liquid-phase and gas-phase syntheses, giving rise to 2D products with high uniformity, nanometer thickness, and large lateral sizes (up to hundreds of micrometers) simultaneously. The success of this strategy highly relies on the speed of "blowing" and control of the amount of reactants. The as-synthesized nanosheet electrodes manifest excellent electrochemical performance for alkali-ion batteries and electrocatalysis. This method opens up a new avenue for economical and massive preparation of good-quality nonlayered 2D nanosheets for energy-related applications and beyond.