Long-Cycle Stability of In Situ Ultraviolet Curable Organic/Inorganic Composite Electrolyte for Solid-State Batteries.

Lithium-ion solid-state batteries with spinel Li4Ti5O12 (LTO) electrodes have significant advantages, such as stability, long life, and good multiplication performance. In this work, the LTO electrode was obtained by the atmospheric plasma spraying method, and a composite solid electrolyte was prepared by in situ ultraviolet (UV) curing on the LTO electrode. The composite solid electrolyte was designed using a soft-hard combination strategy, and the electrolyte was prepared into a composite of a poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) flexible structure and high-conductivity Li1.3Al0.3Ti1.7(PO4)3 (LATP) hard particles. The composite electrolyte exhibited a good ionic conductivity up to 0.35 mS cm-1 at 30 °C and an electrochemical window above 4.0 V. In situ and ex situ electrolytes were assembled into LTO//electrolyte//Li solid-state batteries to investigate their impact on the electrochemical performance of the batteries. As a result, the assembled Li4Ti5O12//in situ electrolytes//Li batteries exhibited excellent rate of performance, and their capacity retention rate was 90% at 0.2 mA/cm2 after 300 cycles. This work provides a new method for the fabrication of novel advanced solid-state electrolytes and electrodes for applications in solid-state batteries.

Preparation and Study of a Simple Three-Matrix Solid Electrolyte Membrane in Air.

Solid-state lithium batteries have attracted much attention due to their special properties of high safety and high energy density. Among them, the polymer electrolyte membrane with high ionic conductivity and a wide electrochemical window is a key part to achieve stable cycling of solid-state batteries. However, the low ionic conductivity and the high interfacial resistance limit its practical application. This work deals with the preparation of a composite solid electrolyte with high mechanical flexibility and non-flammability. Firstly, the crystallinity of the polymer is reduced, and the fluidity of Li+ between the polymer segments is improved by tertiary polymer polymerization. Then, lithium salt is added to form a solpolymer solution to provide Li+ and anion and then an inorganic solid electrolyte is added. As a result, the composite solid electrolyte has a Li+ conductivity (3.18 × 10-4 mS cm-1). The (LiNi0.5Mn1.5O4)LNMO/SPLL (PES-PVC-PVDF-LiBF4-LAZTP)/Li battery has a capacity retention rate of 98.4% after 100 cycles, which is much higher than that without inorganic oxides. This research provides an important reference for developing all-solid-state batteries in the greenhouse.

Terahertz Broadband Absorber Based on a Combined Circular Disc Structure.

To solve the problem of complex structure and narrow absorption band of most of today's terahertz absorbers, this paper proposes and utilizes the finite element (COMSOL) method to numerically simulate a broadband absorber based on a straightforward periodic structure consisting of a disk and concentric ring. The final results show that our designed absorber has an absorption rate of over 99% in the broadband range of 9.06 THz to 9.8 THz and an average of over 97.7% in the ultra-broadband range of 8.62 THz to 10 THz. The reason for the high absorption is explained by the depiction of the electric field on the absorber surface at different frequencies. In addition, the materials for the top pattern of the absorber are replaced by Cu, Ag, or Al, and the absorber still achieves perfect absorption with different metal materials. Due to the perfect symmetry of the absorber structure, the absorber is very polarization-insensitive. The overall design is simple, easy to process and production. Therefore, our research will offer great potential for applications in areas such as terahertz electromagnetic stealth, sensing, and thermal imaging.

Improving oral bioavailability of metformin hydrochloride using water-in-oil microemulsions and analysis of phase behavior after dilution.

Microemulsions show significant promise for enhancing the oral bioavailability of biopharmaceutics classification system (BCS) class II drugs, but how about class III drugs remains unclear. Here we employed metformin hydrochloride (MET) as the model drug and prepared drug-loaded water-in-oil (W/O) microemulsions selecting different hydrophile-lipophile balance (HLB) surfactant systems, using HLB 8 as a cut-off. We examined the phase behaviors of microemulsions after dilution and attempted to correlate these behaviors to drug oral bioavailability. ME-A, including a lower content of surfactants (35%), underwent a transition of W/O emulsion and then became a stable O/W emulsion in a light milky appearance; ME-B, in contrast, introducing a higher content of surfactants (45%), still remained transparent or semitransparent upon dilution. Unexpectedly, ME-A showed significantly higher oral bioavailability, which can be reduced by blocking the lymphatic absorption pathway. Comparatively, the AUC of ME-B is lower, close to MET solution. Both microemulsions behaved similarly in intestinal perfusion test because of the dilution before perfusion, lacking of the important phase transition of W/O emulsion. These findings suggest that W/O microemulsions improve oral bioavailability of BCS class III drug by promoting lymphatic absorption. Analyzing the phase behavior of microemulsions after dilution may help predict the drug oral bioavailability and optimize formulations.

Preparation, transportation mechanisms and brain-targeting evaluation in vivo of a chemical delivery system exploiting the blood-cerebrospinal fluid barrier.

In recent years, specific transportation mechanisms on the blood-brain barrier (BBB) are extensively employed for brain-targeted drug delivery via colloidal nanocarriers. However, in this study, we purposed to exploit the sodium-dependent vitamin C transporter 2 (SVCT2)-mediated transportation on the blood-cerebrospinal fluid barrier to enhance central nervous system penetration of the highly hydrophilic ibuprofen (IBU) by synthesizing a SVCT2-targeted chemical delivery system (CDS), ibuprofen-C6-O-ascorbic acid (IAA). The physicochemical parameters of IAA were determined, and the transporter-mediated transportation mechanism of IAA was explored on a BBB monolayer mode. The overall brain targeting effect of IAA was assayed on mice by measuring the biodistribution of IBU after i.v. administration and calculating the pharmacokinetic parameters and targeting indexes. Results showed that lipophilicity and solubility of IAA was conspicuously improved compared with IBU. At the physiological pH, IAA was stable while in brain homogenates it was easily degraded. Transport studies on the BBB monolayer mode revealed that IAA displayed higher transepithelial permeability than IBU via SVCT2. The biodistribution study in vivo demonstrated that the overall targeting efficiency of IAA was 1.77-fold greater than that of the IBU. In conclusion, the synthetic IAA might be a promising brain-targeted CDS for smuggling small-molecule hydrophilic pharmaceuticals into the brain.

Synthesis of taurine-fluorescein conjugate and evaluation of its retina-targeted efficiency in vitro.

In this work, retinal penetration of fluorescein was achieved in vitro by covalent attachment of taurine to fluorescein, yielding the F-Tau conjugate. Nuclear magnetic resonance (NMR) and high resolution mass spectrometry (HRMS) were used to confirm the successful synthesis of F-Tau. The cellular uptake of F-Tau in adult retinal pigment epithelial cells (ARPE-19) and human retinal microvascular endothelial cells (hRMECs) was visualized via confocal scanning microscopy. The results indicated an improvement of solubility and a reduction of logP of F-Tau compared with fluorescein. As compared with fluorescein, F-Tau showed little toxicity, and was retained longer by cells in uptake experiments. F-Tau also displayed higher transepithelial permeabilities than fluorescein in ARPE-19 and hRMECs monolayer cells (P<0.05). These results showed that taurine may be a useful ligand for targeting small-molecule hydrophobic pharmaceuticals into the retina.