Enabling a High Performance of Mesoporous α-Fe2O3 Anodes by Building a Conformal Coating of Cyclized-PAN Network

Reversible flowering of CuO nanoclusters via conversion reaction for dual-ion Li metal batteries

Dual-ion Li metal batteries based on non-flammable SO₂-in-salt inorganic electrolytes ( Li-SO₂ batteries) offer high safety and energy density. The use of cupric oxide (CuO) as a self-activating cathode material achieves a high specific capacity with cost-effective manufacturing in Li-SO₂ batteries, but its cycle retention performance deteriorates owing to the significant morphological changes of the cathode active materials. Herein, we report the catalytic effect of carbonaceous materials used in the cathode material of Li-SO₂ batteries, which act as templates to help recrystallize the active materials in the activation and conversion reactions. We found that the combination of oxidative-cyclized polyacrylonitrile (PAN) with N-doped carbonaceous materials and multi-yolk-shell CuO (MYS-CuO) nanoclusters as cathode active materials can significantly increase the specific capacity to 315.9 mAh g^- 1 (93.8% of the theoretical value) at 0.2 C, which corresponds to an energy density of 1295 Wh kg_CuO^-1, with a capacity retention of 84.46% at the 200th cycle, and the cathode exhibited an atypical blossom-like morphological change.

Construction of two-dimensional bimetal (Fe-Ti) oxide/carbon/MXene architecture from titanium carbide MXene for ultrahigh-rate lithium-ion storage

The development of battery systems with high specific capacity and power density could fuel various energy-related applications from personal electronics to grid storage. (Fe_2.5Ti_0.5)_1.04O₄ possessing high theoretical specific capacity has been considered as a promising high rate anode material for lithium ion batteries due to the replacement of Fe³⁺ (0.64 Å) by Ti⁴⁺ (0.68 Å) with a larger radius to expand the interlayer space for ion intercalation. However, its extreme volume variation upon cycling as well as poor electrical conductivity hinder its further application. To tackle the above problems, in this work, we successfully synthesized two-dimensional (2D) (Fe_2.5Ti_0.5)_1.04O₄/C/MXene architecture derived from Ti₃C₂T_x MXene via solvo-hydrothermal, ultrasound hybridizing and high temperature annealing processes. The (Fe_2.5Ti_0.5)_1.04O₄/C/MXene shows a high discharge capacity of 757.2 mAh g^-1 after 800 cycles at a current density of 3 A g^-1 with excellent rate performance. The superior electrochemical performances are triggered primarily by the incorporation of carbon and MXene into (Fe_2.5Ti_0.5)_1.04O₄ moiety to construct a 2D layered structure, which can improve the ion diffusion and electron transport. In addition, the synergistic contributions from diffusion controlled and capacitive processes for (Fe_2.5Ti_0.5)_1.04O₄/C/MXene improve the ion diffusion rate and offer high specific capacity at high current density. The MXene-derived synthesis strategy in this work should be a promising pathway to synthesize other anode materials with 2D layered architecture for high performance lithium storage.

α-Fe2O3 hollow meso-microspheres grown on graphene sheets function as a promising counter electrode in dye-sensitized solar cells

Although nanoparticles, nanorods, and nanosheets of α-Fe₂O₃ on graphene sheets have been synthesized, it remains a challenge to grow 3D α-Fe₂O₃ nanomaterials with more sophisticated compositions and structures on the graphene sheets. Herein, we demonstrate a facile solvothermal route under controlled conditions to successfully fabricate 3D α-Fe₂O₃ hollow meso–microspheres on the graphene sheets (α-Fe₂O₃/RGO HMM). Attributed to the combination of the catalytic features of α-Fe₂O₃ hollow meso–microspheres and the high conductivity of graphene, α-Fe₂O₃/RGO HMM exhibited promising electrocatalytic performance as a counter electrode in dye-sensitized solar cells (DSSCs). The DSSCs fabricated with α-Fe₂O₃ HMM displayed high power conversion efficiency of 7.28%, which is comparable with that of Pt (7.71%).

Although nanoparticles, nanorods, and nanosheets of α-Fe₂O₃ on graphene sheets have been synthesized, it remains a challenge to grow 3D α-Fe₂O₃ nanomaterials with more sophisticated compositions and structures on the graphene sheets.

GPCR6A Is a Molecular Target for the Natural Products Gallate and EGCG in Green Tea

SCOPE

The molecular mechanisms whereby gallates in green tea exert metabolic effects are poorly understood.

METHODS AND RESULTS

We found that GPRC6A, a multi-ligand-sensing G-protein-coupled receptor that regulates energy metabolism, sex hormone production, and prostate cancer progression, is a target for gallates. Sodium gallate (SG), gallic acid (GA) > ethyl gallate (EG) > octyl gallate (OG) dose dependently activated ERK in HEK-293 cells transfected with GPRC6A but not in non-transfected controls. SG also stimulated insulin secretion in β-cells isolated from wild-type mice similar to the endogenous GPRC6A ligands, osteocalcin (Ocn) and testosterone (T). Side-chain additions to create OG resulted in loss of GPRC6A agonist activity. Another component of green tea, epigallocatechin 3-gallate (EGCG), dose-dependently inhibited Ocn activation of GPRC6A in HEK-293 cells transfected with GPRC6A and blocked the effect of Ocn in stimulating glucose production in CH10T1/2 cells. Using structural models of the venus fly trap (VFT) and 7-transmembrane (7-TM) domains of GPRC6A, calculations suggest that l-amino acids and GA bind to the VFT, whereas EGCG is calculated to bind to sites in both the VFT and 7-TM.

CONCLUSION

GA and EGCG have offsetting agonist and antagonist effects on GPRC6A that may account for the variable metabolic effect of green tea consumption.

One-Step Self-Assembly Synthesis α-Fe2O3 with Carbon-Coated Nanoparticles for Stabilized and Enhanced Supercapacitors Electrode

A cocoon-like α-Fe2O3 nanocomposite with a novel carbon-coated structure was synthesized via a simple one-step hydrothermal self-assembly method and employed as supercapacitor electrode material. It was observed from electrochemical measurements that the obtained α-Fe2O3@C electrode showed a good specific capacitance (406.9 Fg−1 at 0.5 Ag−1) and excellent cycling stability, with 90.7% specific capacitance retained after 2000 cycles at high current density of 10 Ag−1. These impressive results, presented here, demonstrated that α-Fe2O3@C could be a promising alternative material for application in high energy density storage.