Lithium-ion batteries (LIBs) are widely used in portable energy storage. The capacity of commercial graphite is difficult to improve due to the stoichiometry limit of LiC₆ of graphite, thus new anodes need to be developed to meet the demand of high-energy–density LIB. The growing interest in graphitized carbon nitride (g-C₃N₄) stems from its structural resemblance to graphite and its capacity to offer abundant adsorption and intercalation sites. However, g-C₃N₄, as a semiconductor, has a low lithium transfer rate due to its poor conductivity and high diffusion resistance. Improving the electron transport rate of g-C₃N₄ and reducing the adsorption energy barrier of Li⁺ in g-C₃N₄ are the keys to improving the electrochemical performances of g-C₃N₄. In this study, lignin and melamine were homogeneously mixed using the spray drying method, followed by the preparation of covalently bonded C₃N₄/LC material through a one-step carbonization process. The uniform dispersion of g-C₃N₄ in amorphous carbon can improve the conductivity and reduce the diffusion energy barrier of Li⁺. As a result, the C₃N₄/LC-x anode has better electrochemical behavior, including higher reversible capacity, better rate performance, and cycle stability.

To address the severe damage caused by voids beneath cement concrete pavement slabs, which compromise pavement performance and lifespan, there is an urgent need to develop an economical and efficient grouting material for slab void repair. This study employed a two-step orthogonal experiment design (OED) method to optimize the composition of grouting material. Results show that the plain cement mortar achieves the best flowability, setting time, compressive strength, or flexural strength when the water-to-binder ratio is 0.375, with 20% quartz sand, 2% coal ash, and 5% ground calcium carbonate. For the high-performance cement mortar developed, the optimal water-to-binder ratio is 0.35, with 0.5% redispersible latex powder, 0.2% polypropylene fiber, 0.6% water-reducing agent, 0.8% early-strength agent, and 2.0% expansion agent. Under these optimal conditions, the grouting material with a flowability of 15 s has a compressive strength and flexural strength of 76.98 MPa and 11.89 MPa, respectively, and achieves 77.4% of its 28-day compressive strength and 94.0% of its 28-day flexural strength by day 3. This grouting material also possesses a slight expansion within 0.1% at 3, 7, and 28 days, categorizing it as a micro-expansion mortar. The bond strength at the mortar-concrete interface exceeds the tensile strength of the mortar itself, ensuring no debonding at the interface before grouting material failure. The XRD, SEM, and infrared spectra results explain the early strength development mechanism of this cement mortar.

The ubiquitous presence of tetracycline in water sources due to its prevalent usage in antibiotics poses a potential risk to ecosystems and to human health. There is therefore a dire need for efficient methods of tetracycline removal. To this end, we constructed a series of super-small-sized BiVO₄ composites with different loading amounts of 5 wt%, 10 wt%, 15 wt%, 20 wt%, and 25 wt% on SiO₂ support by a hydrothermal–calcination method for efficient photocatalytic degradation of tetracycline. XRD and SEM results revealed that these composites all exhibited good crystallinity and well-dispersed morphologies. Particularly, the 20 wt% BiVO₄@SiO₂ of this series of composites showed superior photocatalytic performance, with 84.1% efficiency in tetracycline degradation, higher than any of its counterparts. This can be explained by its wide light-absorption range and high charge-separation efficiency, as confirmed by UV-Vis absorption spectra and quenched fluorescence spectra. This work offers a new method for the design and construction of tetracycline degradation photocatalysts.