Light detection and ranging (LiDAR) sensors utilize a near-infrared (NIR) laser with a wavelength of 905 nm. However, LiDAR sensors have weakness in detecting black or dark-tone materials with light-absorbing properties. In this study, SiO2/black TiO2 core/shell nanoparticles (SBT CSNs) were designed as LiDAR-detectable black materials. The SBT CSNs, with sizes of 140, 170, and 200 nm, were fabricated by a series of Stöber, TTIP sol-gel, and modified NaBH4 reduction methods. These SBT CSNs are detectable by a LiDAR sensor and, owing to their core/shell structure with intrapores on the shell (ca. 2–6 nm), they can effectively function as both color and NIR-reflective materials. Moreover, the LiDAR-detectable SBT CSNs exhibited high NIR reflectance (28.2 R%) in a monolayer system and true blackness (L* < 20), along with ecofriendliness and hydrophilicity, making them highly suitable for use in autonomous vehicles.
A facile oxygen (O2) atmospheric plasma treatment is applied to a polyvinyl alcohol (PVA) matrix to enhance its wettability and hydrophilicity. The optimal plasma treatment conditions are determined by varying the applied plasma power and plasma treatment time. A PVA matrix treated with a plasma power of 120 W for 5 s shows the most hydrophilicity owing to successful formation of carbonyl (–CO, >C=O) functional groups without any structural degradation. The plasma-treated PVA matrix is used as the gel-polymer electrolyte of a solid-state supercapacitor (SSC) by immersing solid matrix into various liquid electrolytes, such as sodium sulfate (Na2SO4), sulfuric acid (H2SO4), and potassium hydroxide (KOH). Compared with the pristine PVA-based device, PVA-120W5/Na2SO4-, PVA-120W5/H2SO4-, and PVA-120W5/KOH-based SSCs show 2.03, 2.05, and 2.14 times higher specific capacitances, respectively. The plasma-treated PVA matrix shows increased specific capacitance owing to the increased wettability, which in turn increases the ion transportation and reduces the electrical resistance. This study successfully demonstrates that the electrochemical performance of a SSC can be readily enhanced through plasma treatment for a short time (≤5 s).
Herein, the electrorheological (ER) performances of ER fluids were correlated with their colors to allow for the visual selection of the appropriate fluid for a specific application using naked eyes. A series of TiO2-coated synthetic mica materials colored white, yellow, red, violet, blue, and green (referred to as color mica/TiO2 materials) were fabricated via a facile sol–gel method. The colors were controlled by varying the thickness of the TiO2 coating layer, as the coatings with different thicknesses exhibited different light interference effects. The synthesized color mica/TiO2 materials were mixed with silicone oil to prepare colored ER fluids. The ER performances of the fluids decreased with increasing thickness of the TiO2 layer in the order of white, yellow, red, violet, blue, and green materials. The ER performance of differently colored ER fluids was also affected by the electrical conductivity, dispersion stability, and concentrations of Na+ and Ca2+ ions. This pioneering study may provide a practical strategy for developing new ER fluid systems in future.
In this study, a flexible all-solid-state asymmetric supercapacitor (FASC) device has been successfully fabricated via full recycling of heated tobacco waste (HTW). Tobacco leaves and cellulose acetate tubes have been successfully carbonized (HTW-C) and mixed with metal oxides (MnO2 and Fe3O4) to obtain highly active materials for supercapacitors. Moreover, poly(lactic acid) (PLA) filters have been successfully dissolved in an organic solvent and mixed with the as-prepared active materials using a simple paste mixing method. In addition, flexible MnO2- and Fe3O4-mixed HTW-C/PLA electrodes (C-MnO2/PLA and C-Fe3O4/PLA) have been successfully fabricated using the drop-casting method. The as-synthesized flexible C-MnO2/PLA and C-Fe3O4/PLA electrodes have exhibited excellent electrical conductivity of 378 and 660 μS cm−1, and high specific capacitance of 34.8 and 47.9 mF cm−2 at 1 mA cm−2, respectively. A practical FASC device (C-MnO2/PLA//C-Fe3O4/PLA) has been assembled by employing the C-MnO2/PLA as the positive electrode and C-Fe3O4/PLA as the negative electrode. The as-prepared FASC device showed a remarkable capacitance of 5.80 mF cm−2 at 1 mA cm−2. Additionally, the FASC device manifests stable electrochemical performance under harsh bending conditions, verifying the superb flexibility and sustainability of the device. To the best of our knowledge, this is the first study to report complete recycling of heated tobacco waste to prepare the practical FASC devices. With excellent electrochemical performance, the experiments described in this study successfully demonstrate the possibility of recycling new types of biomass in the future.
Recent advancements in lithium–oxygen (Li–O 2 ) batteries have focused on incorporating redox mediators (RMs) into the electrolyte to address challenges of low energy efficiency and poor cycle life. However, various soluble RMs induce parasitic reactions with Li, compromising the anode stability. In this study, we design optimized Li–O 2 batteries by introducing ZnI 2 into the electrolyte, which serves a dual function: facilitating a stable LiZn/Zn protective layer on the Li metal anode and acting as an effective RM. The in situ formed LiZn/Zn layer prevents I 3− shuttle effects, stabilizing the Li anode and promoting uniform Li plating and stripping. Additionally, the ZnI 2 mediator facilitates rapid conversion of the I − /I 3− and I 3− /I 2 redox couples at the cathode, contributing to a more reversible and lower overpotential Li 2 O 2 cycle. Notably, ZnI 2 enhances early‐stage LiO 2 formation, verified by in situ Raman spectroscopy, which supports uniform sheet‐like Li 2 O 2 deposition and contributes to stable cycling. These synergistic effects caused a significant reduction in the charge potential to less than 3.4 V, enabling over 800 stable cycles. This approach provides a viable pathway to achieving high energy density and long cycle life in Li–O 2 batteries, positioning them for practical applications.