Search

Three triangular friction block configurations are commonly employed in high-speed train brake systems, namely, unperforated, perforated configuration with one circular hole, and perforated with three circular holes. In this study, we adopted these friction block types to investigate the effect of perforated friction block configurations on the brake performance of high-speed trains based on a self-developed brake test rig. The results indicate the significant impact of the number of the holes on the wear behavior, temperature distribution, and vibration characteristics of the brake interface. The friction surface of the unperforated block is covered by wear debris, while the perforated blocks produce less wear debris. Furthermore, the one-hole block exhibits a more uniform temperature distribution and better vibration behavior than that with three holes. The friction brake is a dynamic process, during which separation and attachment between the pad and disc alternatively occur, and the perforated structure on the friction block can both trap and expel the wear debris.

Safety issues related to flammable electrolytes in lithium-ion batteries (LIBs) remain a major challenge for their extended applications. The use of non-flammable phosphate-based electrolytes has proved the validity in inhibiting the combustion of LIBs. However, the strong interaction between Li+and phosphate leads to a dominant solid electrolyte interphase (SEI) with limited electronic shielding, resulting in the poor Li+intercalation at the graphite (Gr) anode when using high-phosphate-content electrolytes. To mitigate this issue and improve Li+insertion, we propose an “In-N-Out” strategy to render phosphates “non-coordinative”. By employing a combination of strongly polar solvents for a “block effect” and weakly polar solvents for a “drag effect”, we reduce the Li+-phosphate interaction. As a result, phosphates remain in the electrolyte phase (“In”), minimizing their impact on the incompatibility with the Gr electrode (“Out”). We have developed a non-flammable electrolyte with high triethyl phosphate (TEP) content (>60 wt.%), demonstrating the excellent ion conductivity (5.94 mS cm −1at 30 °C) and reversible Li+intercalation at a standard concentration (~1 mol L −1). This approach enables the manipulation of multiple electrolyte functions and holds the promise for the development of safe electrochemical energy storage systems using non flammable electrolytes.

Sodium-ion capacitors (SICs) have shown great potential to combine the merits of high-power capability of traditional capacitors and high energy capability of batteries. However, the sluggish kinetics and inferior stability of conventional sodium-ion storage anode materials are major challenges for the practical utilization of SICs. In this work, interconnected urchin-like hollow Na2Ti3O7(Na2Ti3O7-IcUH) chains were designed and prepared by a simple one-step template-assisting method. Through a variety of controlled experiments, we explored how to effectively engineer the crystal-oriented growth and string the urchin-like spheres together. Benefiting from its urchin-like hollow structure and fully exposed (001) facet, the resulting Na2Ti3O7-IcUH exhibits a superior rate capability of 96.2 mA h g–1at 5 A g–1. Meanwhile, the interconnected three-dimensional primary structure endows Na2Ti3O7-IcUH with excellent cyclic stability (15% capacity loss at 5 A g–1after 2000 cycles). By coupling with commercial active carbon, the assembled SIC successfully demonstrates a energy density of 134.3 W h kg–1at a power density of 125 W kg–1and 38.2 W h kg–1at a high-power density of 2500 W kg–1, as well as a superior capacity retention of 75% after 2000 cycles at 2 A g–1within 1–4 V.