A Highly Dispersed Cobalt Electrocatalyst with Electron-Deficient Centers Induced by Boron toward Enhanced Adsorption and Electrocatalysis for Room-Temperature Sodium-Sulfur Batteries.

As vitally prospective candidates for next-generation energy storage systems, room-temperature sodium-sulfur (RT-Na/S) batteries continue to face obstacles in practical implementation due to the severe shuttle effect of sodium polysulfides and sluggish S conversion kinetics. Herein, the study proposes a novel approach involving the design of a B, N co-doped carbon nanotube loaded with highly dispersed and electron-deficient cobalt (Co@BNC) as a highly conductive host for S, aiming to enhance adsorption and catalyze redox reactions. Crucially, the pivotal roles of the carbon substrate in prompting the electrocatalytic activity of Co are elucidated. The experiments and density functional theory (DFT) calculations both demonstrate that after B doping, stronger chemical adsorption toward polysulfides (NaPSs), lower polarization, faster S conversion kinetics, and more complete S transformation are achieved. Therefore, the as-assembled RT-Na/S batteries with S/Co@BNC deliver a high reversible capacity of 626 mAh g-1 over 100 cycles at 0.1 C and excellent durability (416 mAh g-1 over 600 cycles at 0.5 C). Even at 2 C, the capacity retention remains at 61.8%, exhibiting an outstanding rate performance. This work offers a systematic way to develop a novel Co electrocatalyst for RT-Na/S batteries, which can also be effectively applied to other transition metallic electrocatalysts.

P-doped porous carbon from camellia shell for high-performance room temperature sodium-sulfur batteries.

Room-temperature sodium-sulfur batteries are still hampered by severe shuttle effects and sluggish kinetics. Most of the sulfur hosts require high cost and complex synthesis process. Herein, a facile method is proposed to prepare a phosphorous doped porous carbon (CSBP) with abundant defect sites from camellia shell by oxidation pretreatment combined with H3PO4activation. The pretreatment can introduce pores and adjust the structure of biochar precursor, which facilitates the further activation of H3PO4and effectively avoids the occurrence of large agglomeration. Profiting from the synergistic effects of physical confinement and doping effect, the prepared CSBP/S cathode delivers a high reversible capacity of 804 mAh g-1after 100 cycles at 0.1 C and still maintains an outstanding capacity of 458 mAh g-1after 500 cycles at 0.5 C (1 C = 1675 mA g-1). This work provides new insights into the rational design of the microstructures of carbon hosts for high-performance room temperature sodium-sulfur batteries.

Porous hard carbon spheres derived from biomass for high-performance sodium/potassium-ion batteries.

Hard carbon is the most attractive anode material for electrochemical sodium/potassium-ion storage. The preparation of hard carbon spheres directly from the broad sources of biomass is of great interest but barely reported. Herein, we developed a simple two-step hydrothermal method to construct porous carbon microspheres directly from the original waste biomass of camellia shells. The porous carbon microspheres have high specific capacities of 250 mAh g-1and 264.5 mAh g-1at a current density of 100 mA g-1for sodium-ion batteries and potassium-ion batteries, respectively. And it has excellent cycle stability for sodium ions and potassium ions outperforming most reported hard carbons, which is mainly attributed to the microporous structure and spherical morphology. The work paves a way to prepare porous hard carbon spheres directly from biomass for alkali metal-ion batteries.

[Comparisons on chemical constituents of crude and wine-processed Dipsacus asper by using UPLC-Q-TOF/MS].

To compare the quality control indexes and chemical constituents of crude and wine-processed Dipsacus asper. According to Chinese Pharmacopoeia 2015 edition, water content, total ash, acid-insoluble ash and water soluble extract of different processed products were detected. UPLC-Q-TOF/MS approach was established to compare the contents of major constituents in crude and wine-processed D. asper. Moreover, the linearity, precision, stability, repeatability and recoveries of the approach were well studied. The results of water content, total ash, acid-insoluble ash and water-soluble extract of crude and wine-processed D. asper were all in line with the requirements of the Chinese Pharmacopoeia 2015 edition. Meanwhile, 20 main chemical constituents were identified by using UPLC-Q-TOF/MS. After wine-processing, the contents of asperosaponin Ⅵ, acetylate analogues and caffeic acid were significantly increased, while the contents of other phenolic components such as dicaffeoylquinic acid were decreased significantly, which may be which may be the main reason for different clinical efficacy of crude and wine-processed D. asper.