Enhancing Quasi-Solid-State Lithium-Metal Battery Performance: Multi-Interlayer, Melt-Infused Lithium and Lithiophilic Coating Strategies for Interfacial Stability in Li||VS2-DSGNS-LATP|PEO-PVDF||NMC622-Al2O3 Systems

The development of quasi-solid-state lithium metal batteries (QSSLMBs) is hindered by inadequate interfacial contact, poor wettability between electrodes and quasi-solid-state electrolytes, and significant volume changes during long-term cycling, leading to safety risks and cataclysmic failures. Here, we report an innovative approach to enhance interfacial properties through the in situ construction of QSSLMBs. A multilayer design integrates a microwave-synthesized Li1.3Al0.3Ti1.7(PO4)3 (LATP) ceramic electrolyte, which is surface-coated with a lithiophilic conductive ink comprising VS2 and disulfonated functionalized graphene nanosheets (VS2-DSGNS) using a low-cost nail-polish binder. Subsequently, a few drops of LiPF6 in EC/DMC liquid electrolyte (LE) are impregnated into the uncoated side of the LATP surface. The quasi-solid-state electrolyte pellet of LATP-VS2-DSGNS surface was allowed to be in contact with the molten Li and held until Li flowed into the LATP-VS2-DSGNS surface completely via a "melt-infusion strategy" as an anode side. Additionally, a heterogeneous polymer matrix consisting of poly(ethylene oxide) (PEO) and poly(vinylidene difluoride) (PVDF) as a polymer interlayer is fabricated using a solution casting technique for improving the wettability between the LE impregnated side of LATP and cathode, to enhance overall charge transfer kinetics. The assembled symmetric cells, Li||LATP-VS2-DSGNS||Li and Li||PEO-PVDF/LE-LATP||Li, demonstrate high lithium-ion conductivities of 3.69 × 10-4 and 1.02 × 10-3 S cm-1, respectively, with impressive lithium-ion transfer numbers of 0.84 and 0.93 at 25 °C. Both cells exhibit a highly reversible lithium stripping/plating cycling process for over 600 h, with minimal voltage polarization of 10 and 31.6 mV, across a broad redox window (-1 to 6 V), effectively inhibiting lithium dendrite formation. Furthermore, the combination of a surface-modified Al2O3 dry-coated, high-nickel NMC622 cathode with the PEO-PVDF|LATP-VS2-DSGNS||Molten-Li architecture in a CR2032 coin-type full-cell delivers a galvanostatic discharge capacity of 130.6 mAh g-1 at a 1C rate after 200 cycles, achieving 84.3% capacity retention, thereby demonstrating substantial reduction in interfacial resistance and enhanced stable battery performance of QSSLMBs.

Magnetic graphene oxide functionalized alginate-g-poly(2-hydroxypropylmethacrylamide) nanoplatform for near-infrared light/pH/magnetic field-sensitive drug release and chemo/phototherapy

Multifunctional nanoplatforms developed from natural polymers and graphene oxide (GO) with enhanced biological/physicochemical features have recently attracted attention in the biomedical field. Herein, a new multifunctional near-infrared (NIR) light-, pH- and magnetic field-sensitive hybrid nanoplatform (mGO@AL-g-PHPM@ICG/EP) is developed by combining iron oxide decorated graphene oxide nanosheets (mGO) and poly(2-hydroxypropylmethacrylamide) grafted alginate (AL-g-PHPM) copolymer loaded with indocyanine green (ICG) and etoposide (EP) for chemo/phototherapy. The functional groups, specific crystal structure, size, morphology, and thermal stability of the nanoplatform were fully characterized by XRD, UV, FTIR, AFM/TEM/FE-SEM, VSM, DSC/TG, and BET analyses. In this platform, the mGO and ICG, as phototherapeutic agents, demonstrate excellent thermal effects and singlet oxygen production under NIR-light (808 nm) irradiation. The XRD and DSC analysis confirmed the amorphous state of the ICG/EP in the nanoparticles. In vitro photothermal tests proved that the mGO@AL-g-PHPM@ICG/EP nanoparticles had outstanding light stability and photothermal conversion ability. The in vitro release profiles presented NIR light-, pH- and magnetic field-controlled EP/ICG release behaviors. In vitro experiments demonstrated the excellent antitumor activity of the mGO@AL-g-PHPM@ICG/EP against H1299 tumor cells under NIR laser. Benefiting from its low-cost, facile preparation, and good dual-modal therapy, the mGO@AL-g-PHPM@ICG/EP nanoplatform holds great promise in multi-stimuli-sensitive drug delivery and chemo/phototherapy.

Assessment on the Effect of Sulfuric Acid Concentration on Physicochemical Properties of Sulfated-Titania Catalyst and Glycerol Acetylation Performance

In this research, a solid acid catalyst was synthesized to catalyse glycerol acetylation into acetins. The sulphated-titania catalysts were prepared via the wet impregnation method at different sulfuric acid concentrations (5%, 10%, 15%, and 20%) and denoted as 5SA, 10SA, 15SA, and 20SA, respectively. The synthesized catalysts were characterized using FTIR, XRD, TGA, BET, NH3-TPD, XRF, and SEM-EDX. The synthesized catalysts were tested on glycerol acetylation reaction at conditions: 0.5 g catalyst loading, 100–120 °C temperature, 1:6 glycerol/acetic acid molar ratios, and 2–4 h reaction time. The final product obtained was analysed using GC-FID. An increment in sulfuric acid concentration reduces the surface area, pore volume, and particles size. However, the increment has increased the number of active sites (Lewis acid) and strong acid strength. 15SA catalyst exhibited excellent glycerol conversion (>90%) and the highest selectivity of triacetin (42%). Besides sufficient surface area (1.9 m2 g−1) and good porosity structure, the great performance of the 15SA catalyst was attributed to its high acid site density (342.6 µmol g−1) and the high active site of metal oxide (95%).