Dual Cross-Linked Multifunctional Binder for High-Performance Lithium–Sulfur Batteries

Lithium–sulfur batteries suffer from volume variation, insulation of sulfur, and a severe shuttle effect, leading to an inferior cycling performance. Herein, a dual cross-linked binder (CPS), which contains chemical covalent bonds and physical hydrogen bonds, is fabricated for lithium–sulfur batteries through carboxymethyl cellulose conjugated with catechol groups and thiolated branched polyethylenimine. The chemical covalent cross-linked bonds are formed via the Michael addition reaction that avoids consumption of catechol groups. The dynamic hydrogen bonds consume the stress energy and repair the cracks, which are caused by the remarkable volume change of sulfur. Combining the rigid and soft moieties, polar groups, and dual cross-linked structure in the CPS, the CPS prominently tolerates and buffers the huge volume change of active materials, resulting in maintenance of the cathode integrity. Additionally, the CPS effectively immobilizes the lithium polysulfides into the cathodes, remarkably accelerates the reaction kinetics, and significantly facilitates lithium-ion diffusion. As a result, the sulfur cathode with CPS exhibits a high initial capacity of 1380 mAh g–1. At a mass loading of 8.5 mg cm–2 and an electrolyte/sulfur ratio of 5 μL mg–1, the sulfur cathode with CPS retains 627 mAh g–1 after 100 cycles at a rate of 0.5 C

Ultrahigh Energy-Storage Density of BaTiO₃‑Based Ceramics via the Interfacial Polarization Strategy

Lead-free dielectric capacitors are excellent candidates for pulsed power devices. However, their low breakdown strength (Eb) strongly limits their energy-storage performance. In this study, Sr0.7Bi0.2TiO3 (SBT) and Bi­(Mg0.5Hf0.5)­O3 (BMH) were introduced into BaTiO3 (BT) ceramics to suppress interfacial polarization and modulate the microstructure. The results show that the introduction of SBT and BMH increases the band gap width, reduces the domain size, and, most importantly, successfully attenuates the interfacial polarization. Significantly enhanced Eb values were obtained in (1 – x)­(0.65BaTiO3–0.35Sr0.7Bi0.2TiO3)–xBi­(Mg0.5Hf0.5)­O3 (BSBT–xBMH) ceramics. Meanwhile, the interfacial polarization was reduced to near zero in the sample with x = 0.10, achieving an ultrahigh Eb (64 kV/mm) and a very large recoverable energy-storage density (Wrec ≈ 9.13 J/cm3). In addition, the sample has excellent thermal stability (in line with EIA-X7R standards) and frequency stability. These properties indicate that the BSBT–0.10BMH ceramic holds promising potential for the application of pulsed power devices

Outstanding Energy Storage Performance of NBT-Based Ceramics under Moderate Electric Field Achieved via Antiferroelectric Engineering

Ultrahigh energy-storage performance of dielectric ceramic capacitors is generally achieved under high electric fields (HEFs). However, the HEFs strongly limit the miniaturization, integration, and lifetime of the dielectric energy-storage capacitors. Thus, it is necessary to develop new energy-storage materials with excellent energy-storage densities under moderate electric fields (MEFs). Herein, the antiferroelectric material Ag0.9Ca0.05NbO3 (ACN) was used to modify the relaxor ferroelectric material 0.6Na0.5Bi0.5TiO3–0.4Sr0.7Bi0.2TiO3 (NBT-SBT). The introduction of ACN results in high polarization strength, regulated composition of rhombohedral (R3c) and tetragonal (P4bm), nanodomains, and refined grain size. An outstanding recoverable energy density (Wrec = 4.6 J/cm3) and high efficiency (η = 82%) were realized under an MEF of 260 kV/cm in 4 mol % ACN-modified NBT-SBT ceramic. The first-principles calculation reveals that the interaction between Bi and O is the intrinsic mechanism of the increased polarization. A new parameter ΔP/Eb was proposed to be used as the figure of merit to measure the energy-storage performance under MEFs (∼200–300 kV/cm). This work paves a new way to explore energy-storage materials with excellent-performance MEFs

Image_1_Six new polyphenolic metabolites isolated from the Suillus granulatus and their cytotoxicity against HepG2 cells.pdf

Edible mushrooms are an important source of nutraceuticals and for the discovery of bioactive metabolites as pharmaceuticals. In this work, six new polyphenolic metabolites suillusol A-D (1–4), suillusinoic acid (5), ethyl suillusinoate (6), were isolated from the Suillus granulatus. The structures of new compounds were elucidated using high-resolution electrospray ionization mass spectroscopy, nuclear magnetic resonance data, and single-crystal X-ray diffraction analysis. As far as we know, compound 1 represents an unprecedented type of natural product and compound 3 represents a new type of polyphenol fungal pigment, which may be biosynthetically related to thelephoric acid. The cytotoxicity against HepG2 cells of the new compounds were also evaluated. Compound 2 demonstrate significant inhibitory activity against HepG2 cells with IC50 values of 10.85 μM, surpassing that of positive control cisplatin. Moreover, compound 1 and 3 also exhibited moderate cytotoxic activity with their IC50 values measured at 35.60 and 32.62 μM, respectively. Our results indicate that S. granulatus is a rich source of chemical constituents that may provide new lead compounds for the development of anticancer agents.</p