High power and stable P-doped yolk-shell structured Si@C anode simultaneously enhancing conductivity and Li+ diffusion kinetics

Silicon is a low price and high capacity anode material for lithium-ion batteries. The yolk-shell structure can effectively accommodate Si expansion to improve stability. However, the limited rate performance of Si anodes can’t meet people’s growing demand for high power density. Herein, the phosphorus-doped yolk-shell Si@C materials (P-doped Si@C) were prepared through carbon coating on P-doped Si/SiOx matrix to obtain high power and stable devices. Therefore, the as-prepared P-doped Si@C electrodes delivered a rapid increase in Coulombic efficiency from 74.4% to 99.6% after only 6 cycles, high capacity retention of ∼ 95% over 800 cycles at 4 A·g−1, and great rate capability (510 mAh·g−1 at 35 A·g−1). As a result, P-doped Si@C anodes paired with commercial activated carbon and LiFePO4 cathode to assemble lithium-ion capacitor (high power density of ∼ 61,080 W·kg−1 at 20 A·g−1) and lithium-ion full cell (good rate performance with 68.3 mAh·g−1 at 5 C), respectively. This work can provide an effective way to further improve power density and stability for energy storage devices

Standards-Based UPLC-Q-Exactive Orbitrap MS Systematically Identifies 36 Bioactive Compounds in <i>Ampelopsis grossedentata</i> (Vine Tea)

Ampelopsis grossedentata (vine tea) has been used as a detoxifying beverage in China for centuries. To systematically identify its bioactive compounds, the study adopted standards-based ultra-high-performance liquid chromatography coupled with quadrupole/electrostatic field orbitrap high-resolution mass spectrometry (UPLC-Q-Exactive Orbitrap MS) analysis. The analysis was conducted under a negative ion model and the data were collected using the Xcalibur 4.1 software package. Based on comparisons with authentic standards, 36 bioactive compounds were putatively identified by four parameters: retention time, molecular ion peak, MS/MS profile, and characteristic fragments. These bioactive compounds include two chromones (noreugenin and 3,5,7-trihydroxychromone), 15 flavonoids (S-eriodictyol, S-naringenin, luteolin, ampelopsin, taxifolin, myricetin, quercetin, viscidulin I, kaempferol, myricetin 3-O-galactoside, myricitrin, avicularin, quercitrin, isorhamnetin-3-O-β-D-glucoside, and afzelin), four phenolic acids (gallic acid, 3,4-dihydroxy-5-methoxybenzoic acid, syringic acid, and ellagic acid), five tea polyphenols (epigallocatechin, epigallocatechin gallate, gallocatechin gallate, epicatechin gallate, and catechin gallate), three chalcones (phloridzin, phloretin, and naringenin chalcone), one stilbene (polydatin), two lipids (myristic acid and ethyl stearate), one sugar (D-gluconic acid), one amino acid (L-tryptophan), one triterpenoid (oleanolic acid) and one alkaloid (jervine). Notably, the jervine identification is the first report regarding the occurrence of alkaloid in the plant. Two chromones may be the parent skeleton to biosynthesize the flavonoid in A. grossedentata.</i

Quantification of adulterated fox-derived components in meat products by drop digital polymerase chain reaction

This paper reported a novel approach to quantification of adulterated fox-derived components in meat products by drop digital polymerase chain reaction (ddPCR). By using the F2 gene as the target gene of fox, a single primer was designed to identify the adulteration that had been added either inadvertently or deliberately during the process. In this paper, the fox meat was used as the experimental materials and a relationship was established between fox mass and copy number by extracting DNA and using DNA concentration as an intermediary. The results that across the dynamic range, the relationships between meat mass and DNA concentration were nearly linear (R2 = 0.9986), as was the relationship between DNA concentration and DNA copy number (R2 = 0.9992). Based on the DNA concentration, the following formulas were developed about the relationship between fox meat mass (Mfox) and DNA copy number (C): Mfox = 0.05C + 2.7

Anti-pulverization intermetallic Fe–Sn anchored on N-doped carbon anode boosted superior power and stable lithium storage

Tin (Sn) anode suffers from considerable volume deformation, generating vast dilatation-induced stresses leading to pulverization for lithium-ion batteries (LIBs). Herein, the Sn–Fe–C composite anode material with a jujube cake-like structure where Sn/FeSn2 metalcore anchored on an N-doped carbon matrix is constructed. During the lithiation process, the intermetallic Fe–Sn (FeSn2) generates Fe nanoparticles, which are uniformly distributed in the Sn matrix to relieve internal stress and create a conductive network, thus enhancing electron conduction and ion diffusion kinetics. In addition, the N-doped carbon matrix maintains the material structural integrity and improves overall conductivity. Consequently, the Sn–Fe–C anode delivers a high reversible 400 mAh g−1 over 1100 cycles at 5 A g−1 (capacity retention of up to 90.9%) and rate performance (237 mAh g−1 at 20 A g−1). Sn–Fe–C anode pairs with porous carbon (PC) cathode to assemble lithium-ion capacitors (Sn–Fe–C || PC LICs), which show a maximum energy density of 203.8 Wh kg−1, an excellent power density of 23925.3 W kg−1, and energy retention rate of 72.9% after 18,000 cycles at 1 A g−1. The Sn–Fe–C material as an anti-pulverization anode could be a potential application for high-performance LIBs and LICs in the future