4 research outputs found
High Chaos Induced Multiple-Anion-Rich Solvation Structure Enabling Ultrahigh Voltage and Wide Temperature Lithium-Metal Batteries
The optimal electrolyte for ultrahigh energy density
(>400 Wh/kg)
lithium-metal batteries with a LiNi0.8Co0.1Mn0.1O2 cathode is required to withstand high voltage
(≥4.7 V) and be adaptable over a wide temperature range. However,
the battery performance is degraded by aggressive electrode–electrolyte
reactions at high temperature and high voltage, while excessive growth
of lithium dendrites usually occurs due to poor kinetics at low temperature.
Accordingly, the development of electrolytes has encountered challenges
in that there is almost no electrolyte simultaneously meeting the
above requirements. Herein, a high chaos electrolyte design strategy
is proposed, which promotes the formation of weak solvation structures
involving multiple anions. By tailoring a Li+-EMC-DMC-DFOB–-PO2F2–-PF6– multiple-anion-rich solvation sheath,
a robust inorganic-rich interphase is obtained for the electrode–electrolyte
interphase (EEI), which is resistant to the intense interfacial reactions
at high voltage (4.7 V) and high temperature (45 °C). In addition,
the Li+ solvation is weakened by the multiple-anion solvation
structure, which is a benefit to Li+ desolventization at
low temperature (−30 °C), greatly improving the charge
transfer kinetics and inhibiting the lithium dendrite growth. This
work provides an innovative strategy to manipulate the high chaos
electrolyte to further optimize solvation chemistry for high voltage
and wide temperature applications
Transition-Metal-Free Cleavage of C–C Triple Bonds in Aromatic Alkynes with S<sub>8</sub> and Amides Leading to Aryl Thioamides
A novel transition-metal-free cleavage
reaction of C–C triple
bonds in aromatic alkynes with S<sub>8</sub> and amides furnishes
aryl thioamides in moderate to excellent yields. The remarkable features
of this thioamidation include the metal-free cleavage of C–C
triple bond, mild reaction conditions, as well as wide substrate scope
that is particularly compatible with some internal aromatic alkynes
and acetamides
Entropy-Driven Enhancement of the Conductivity and Phase Purity of Na<sub>4</sub>Fe<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub>P<sub>2</sub>O<sub>7</sub> as the Superior Cathode in Sodium-Ion Batteries
Na4Fe3(PO4)2(P2O7) (NFPP) is regarded as a promising cathode
material
for sodium-ion batteries (SIBs) owing to its low cost, easy manufacture,
environmental purity, high structural stability, unique three-dimensional
Na-ion diffusion channels, and appropriate working voltage. However,
for NFPP, the low conductivity of electrons and ions limits their
capacity and power density. The generation of NaFeP2O7 and NaFePO4 inhibits the diffusion of sodium ions
and reduces reversible capacity and rate performance during the manufacturing
process in synthesis methods. Herein, we report an entropy-driven
approach to enhance the electronic conductivity and, concurrently,
phase purity of NFPP as the superior cathode in sodium-ion batteries.
This approach was realized via Ti ions substituting different ratios
of Fe-occupied sites in the NFPP lattice (denoted as NTFPP-X, T is
the Ti in the lattice, X is the ratio of Ti-substitution) with the
configurational entropic increment of the lattice structures from
0.68 R to 0.79 R. Specifically, 5% Ti-substituted lattice (NTFPP-0.05)
inducing entropic augmentation not only improves the electronic conductivity
from 7.1 × 10–2 S/m to 8.6 × 10–2 S/m but also generates the pure-phase of NFPP (suppressing the impure
phases of the NaFeP2O7 and NaFePO4) of the lattice structure, which is validated by a series of characterizations,
including powder X-ray diffraction (XRD), Fourier transform infrared
spectra (FT-IR), X-ray photoelectron spectroscopy (XPS), and density
functional theory (DFT). Benefiting from the Ti replacement in the
lattice, the optimal NTFPP-0.05 composite shows a high first discharge
capacity (118.5 mAh g–1 at 0.1 C), superior rate
performance (70.5 mAh g–1 at 10 C), and excellent
long cycling life (1200 cycles at 10 C with capacity retention of
86.9%). This research proposes a new entropy-driven approach to improve
the electrochemical performance of NFPP and reports a low-cost, ultrastable,
and high-rate cathode material of NTFPP-0.05 for SIBs
<i>o</i>‑Semiquinone Radical and <i>o</i>‑Benzoquinone Selectively Degrade Aniline Contaminants in the Periodate-Mediated Advanced Oxidation Process
Advanced
oxidation processes (AOPs) often employ strong oxidizing
inorganic radicals (e.g., hydroxyl and sulfate radicals) to oxidize
contaminants in water treatment. However, the water matrix could scavenge
the strong oxidizing radicals, significantly deteriorating the treatment
efficiency. Here, we report a periodate/catechol process in which
reactive quinone species (RQS) including the o-semiquinone
radical (o-SQ•–) and o-benzoquinone (o-Q) were dominant to effectively
degrade anilines within 60 s. The second-order reaction rate constants
of o-SQ•– and o-Q with aniline were determined to be 1.0 × 108 and
4.0 × 103 M–1 s–1, respectively, at pH 7.0, which accounted for 21% and 79% of the
degradation of aniline with a periodate-to-catechol molar ratio of
1:1. The major byproducts were generated via addition or polymerization.
The RQS-based process exhibited excellent anti-interference performance
in the degradation of aniline-containing contaminants in real water
samples in the presence of diverse inorganic ions and organics. Subsequently,
we extended the RQS-based process by employing tea extract and dissolved
organic matter as catechol replacements as well as metal ions [e.g.,
Fe(III) or Cu(II)] as periodate replacements, which also exhibited
good performance in aniline degradation. This study provides a novel
strategy to develop RQS-based AOPs for the highly selective degradation
of aniline-containing emerging contaminants