Aqueous Zn batteries promise high energy density but suffer from Zn dendritic growth and poor low‐temperature performance. Here, we overcome both challenges by using an eutectic 7.6 m ZnCl2 aqueous ...electrolyte with 0.05 m SnCl2 additive, which in situ forms a zincophilic/zincophobic Sn/Zn5(OH)8Cl2⋅H2O bilayer interphase and enables low temperature operation. Zincophilic Sn decreases Zn plating/stripping overpotential and promotes uniform Zn plating, while zincophobic Zn5(OH)8Cl2⋅H2O top‐layer suppresses Zn dendrite growth. The eutectic electrolyte has a high ionic conductivity of ≈0.8 mS cm−1 even at −70 °C due to the distortion of hydrogen bond network by solvated Zn2+ and Cl−. The eutectic electrolyte enables Zn∥Ti half‐cell a high Coulombic efficiency (CE) of >99.7 % for 200 cycles and Zn∥Zn cell steady charge/discharge for 500 h with a low overpotential of 8 mV at 3 mA cm−2. Practically, Zn∥VOPO4 batteries maintain >95 % capacity with a CE of >99.9 % for 200 cycles at −50 °C, and retain ≈30 % capacity at −70 °C of that at 20 °C.
A highly reversible Zn anode working at low temperature is achieved by introducing SnCl2 into eutectic ZnCl2 aqueous electrolyte to form a zincophilic–zincophobic interfacial layer on the Zn anode in situ. The bottom layer of Sn facilitates uniform Zn deposition, while the top layer of zincophobic Zn5(OH)8Cl2 H2O facilitates Zn2+ diffusion and avoids Zn dendrites. The eutectic composition enhances the low temperature conductivity.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
P2‐type layered oxides suffer from an ordered Na+/vacancy arrangement and P2→O2/OP4 phase transitions, leading them to exhibit multiple voltage plateaus upon Na+ extraction/insertion. The deficient ...sodium in the P2‐type cathode easily induces the bad structural stability at deep desodiation states and limited reversible capacity during Na+ de/insertion. These drawbacks cause poor rate capability and fast capacity decay in most P2‐type layered oxides. To address these challenges, a novel high sodium content (0.85) and plateau‐free P2‐type cathode‐Na0.85Li0.12Ni0.22Mn0.66O2 (P2‐NLNMO) was developed. The complete solid‐solution reaction over a wide voltage range ensures both fast Na+ mobility (10−11 to 10−10 cm2 s−1) and small volume variation (1.7 %). The high sodium content P2‐NLNMO exhibits a higher reversible capacity of 123.4 mA h g−1, superior rate capability of 79.3 mA h g−1 at 20 C, and 85.4 % capacity retention after 500 cycles at 5 C. The sufficient Na and complete solid‐solution reaction are critical to realizing high‐performance P2‐type cathodes for sodium‐ion batteries.
A high sodium content (0.85) and plateau‐free P2‐type cathode, Na0.85Li0.12Ni0.22Mn0.66O2, is developed for sodium‐ion batteries. The sodium content promises a large specific capacity of 123.4 mA h g−1 with an average working voltage as high as 3.5 V. The complete solid‐solution reaction over a wide voltage range ensures small volume variation (1.7 %) and fast Na+ kinetics (10−10 to 10−11 cm2 s−1), contributing to both excellent cycling stability and rate capability.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
To promote the development of high energy Li-O
batteries, it is important to design and construct a suitable and effective oxygen-breathing cathode. Herein, activated cobalt-nitrogen-doped carbon ...nanotube/carbon nanofiber composites (Co-N-CNT/CNF) as the effective cathodes for Li-O
batteries are prepared by in situ chemical vapor deposition (CVD). The unique architecture of these electrodes facilitates the rapid oxygen diffusion and electrolyte penetration. Meanwhile, the nitrogen-doped carbon nanotube/carbon nanofiber (N-CNT/CNF) and Co/CoN
serve as reaction sites to promote the formation/decomposition of discharge product. Li-O
batteries with Co-N-CNT/CNF cathodes exhibit superior electrochemical performance in terms of a positive discharge plateau (2.81 V) and a low charge overpotential (0.61 V). Besides, Li-O
batteries also present a high discharge capacity (11512.4 mAh g
at 100 mA g
), and a long cycle life (130 cycles). Meanwhile, the Co-N-CNT/CNF cathode also has an excellent flexibility, thus the assembled flexible battery with Co-N-CNT/CNF can work normally and hold a wonderful capacity rate under various bending conditions.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Three-dimensional biofilm-electrode reactors (3D-BERs), which possess a large effective area to drive the reductive degradation of contaminants, have recently attracted attention for wastewater ...treatment. There have been few studies of the potential and risks of the application of this system on the removal of antibiotics. Here four 3D-BERs were designed to initially assess the potential for electrical stimulation to remove sulfamethoxazole (SMX), tetracycline (TC) and chemical oxygen demand, and to study the fate of the corresponding antibiotic resistance genes. The results indicated that the 3D-BER could significantly reduce antibiotic concentrations in wastewater, achieving removal rates of 88.9–93.5% and 89.3–95.6% for SMX and TC, respectively. The concentrations of target genes (sulI, sulII, sulIII, tetA, tetC, tetO, tetQ, and tetW) in a granular-activated carbon (GAC) cathode were higher than those in a GAC anode in the 3D-BR (reactor with biological sludge and no voltage) and 3D-BER. An obvious increasing trend in the relative abundances of all target genes was observed in the GAC. A low current density could not increase the development of sul and tet genes in the 3D-BER. The total resistance was in the following order: 3D-BER > 3D-BR > 3D-ER (reactor with 0.8 V and without biological sludge). In addition, the dehydrogenase activity of the microorganisms in the 3D-BER was significantly higher than in the 3D-BR (p < 0.05). High-throughput sequencing revealed that the microbial communities and relative abundance at the phyla level were affected by current stimulation.
•Satisfactory removal of sulfamethoxazole and tetracycline were acquired in 3D-BER.•Antibiotic resistance genes in a GAC cathode were higher than those in a GAC anode.•A low current density could not increase the development of antibiotic resistance genes.•Microbial communities were significantly affected by current stimulation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The evolution of cost‐effective and reserve‐rich nonprecious metals (NPMs) to replace precious metal electrocatalysts is of significant interest in modern electrocatalysis. The confinement effects in ...NPM‐based nanoparticles encapsulated in carbon nanoshells have been considered as an emerging and efficient way to special types of electrocatalysts which facilitate electrocatalytic activity and stability, even under rigorous conditions. This review focuses on the unique individual carbon encapsulation for high‐performance design of NPM‐based electrocatalysts, outlining all confinement synthesis methods, mechanistic studies on confinement effects, and the emerging practical reactions. It begins first introducing the synthetic methods for NPM‐based core@carbon shell electrocatalysts, and then follows clarification of the relationship between the fundamental confinement effects and the performance improvement of carbon shell encapsulating NPM‐based electrocatalysts. Further and detailed discussions on the alloying effect, doping effect, and heterojunction effect of the NPM‐based core to alter the electronic situation which affects the electrocatalytic performance are subsequently provided. Finally, the review provides a perspective on challenges and opportunities in future research with respect to both in‐depth theoretical research and potential design concept of such NPM‐based core@carbon shell electrocatalysts.
Individual nonprecious metal (NPM)‐based core@carbon shell electrocatalysts have attracted extensive attention as one of the promising electrocatalytic materials. Confined within the carbon shell endows the integral electrocatalysts with good physical and chemical properties. Further alloying, doping, and heterojunction design of the cores provide abundant options for diverse electrocatalytic reactions. The structure–performance relationship is comprehensively reviewed via the experimental results and theoretical calculations.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Electrocatalysts for hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR) are crucial for water splitting and fuel cells/metal–air batteries, of ...which the benchmark catalysts for HER/ORR and OER are expensive and scarce Pt‐based and Ir/Ru‐based compounds, respectively. In spite of this, no trifunctional electrocatalyst for HER, OER, and ORR with an acceptable performance have been reported. In response, herein, as a proof‐of‐concept experiment, this study first in situ couples element abundant FeM (M = Ni, Co) particles with the nitrogen‐doped porous carbon (NPC) by a facile and scalable strategy. Unexpectedly, the resulted FeM/NPC exhibits superior trifunctional catalytic activities for HER, OER, and ORR even in the same electrolyte, which can be attributed to the synergistic advantages of FeM/NPC in terms of its good conductivity, highly porous structure, high Brunauer−Emmett−Teller (BET) surface area, nitrogen doping, and the intimate contact of FeM and NPC. Furthermore, such trifunctional catalyst makes the overall water splitting work at moderate overpotential, and endows the assembled Zn−air battery with a good performance and impressive capacity to self‐power the overall water splitting, demonstrating its feasibility for practical application.
In situ anchoring FeM (Ni/Co) alloy on a nitrogen‐doped porous carbon hybrid exhibits appreciable trifunctional electrocatalytic performances for oxygen evolution reaction, hydrogen evolution reaction, and oxygen reduction reaction in alkaline medium, thus making the overall water splitting and operation of the Zn‐air battery convenient, demonstrating its feasibility for practical application.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The direct, Pd-catalyzed ortho C–H methylation and fluorination of benzaldehydes have been accomplished using commercially available orthanilic acids as transient directing groups. In these ...reactions, the 1-fluoro-2,4,6-trimethylpyridinium salts can be either a bystanding F+ oxidant or an electrophilic fluorinating reagent. An X-ray crystal structure of a benzaldehyde ortho C–H palladation intermediate was obtained using triphenylphosphine as the stabilizing ligand.
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IJS, KILJ, NUK, PNG, UL, UM
Single‐atom catalysts (SACs) show great promise for electrochemical CO2 reduction reaction (CRR), but the low density of active sites and the poor electrical conduction and mass transport of the ...single‐atom electrode greatly limit their performance. Herein, we prepared a nickel single‐atom electrode consisting of isolated, high‐density and low‐valent nickel(I) sites anchored on a self‐standing N‐doped carbon nanotube array with nickel–copper alloy encapsulation on a carbon‐fiber paper. The combination of single‐atom nickel(I) sites and self‐standing array structure gives rise to an excellent electrocatalytic CO2 reduction performance. The introduction of copper tunes the d‐band electron configuration and enhances the adsorption of hydrogen, which impedes the hydrogen evolution reaction. The single‐nickel‐atom electrode exhibits a specific current density of −32.87 mA cm−2 and turnover frequency of 1962 h−1 at a mild overpotential of 620 mV for CO formation with 97 % Faradic efficiency.
If I had a nickel: An efficient NiI single‐atom electrode for the electrochemical CO2 reduction reaction is realized by combining the advantages of a single‐atom catalyst and a self‐standing nanoarray architecture.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The FNAL+BNL measurements for muon
g
-
2
is
4.2
σ
above the SM prediction, and the Berkeley
133
Cs measurement for the fine-structure constant
α
em
leads to the SM prediction for electron
g
-
2
which ...is
2.4
σ
above the experimental value. Hence, a joint explanation of both anomalies requires a positive contribution to muon
g
-
2
and a negative contribution to electron
g
-
2
, which is rather challenging. In this work we explore the possibility of such a joint explanation in the minimal supersymmetric standard model (MSSM). Assuming no universality between smuon and selectron soft masses, we find out a part of parameter space for a joint explanation at
2
σ
level, i.e.,
μ
M
1
,
μ
M
2
<
0
,
m
L
1
,
m
E
2
<
200
GeV,
m
L
2
being much larger than the soft masses of other sleptons,
|
M
1
|
<
125
GeV and
μ
<
400
GeV. This part of parameter space can survive LHC and LEP constraints, but gives an over-abundance for dark matter if the bino-like lightest neutralino is assumed to be the dark matter candidate. With the assumption that the dark matter candidate is a superWIMP (say a pseudo-goldstino in multi-sector SUSY breaking scenarios, whose mass can be as light as GeV and produced from the late-decay of the thermally freeze-out lightest neutralino), the dark matter problem can be avoided. So, we conclude that the MSSM may give a joint explanation for the muon and electron
g
-
2
anomalies at
2
σ
level (the muon
g
-
2
anomaly can be even ameliorated to
1
σ
).
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The effect of H2O in electrolytes and in electrode lattices on the thermodynamics and kinetics of reversible multivalent‐ion intercalation chemistry based on a model platform of layered VOPO4 has ...been investigated. The presence of H2O at the electrolyte/electrode interface plays a key role in assisting Zn2+ diffusion from electrolyte to the surface, while H2O in the lattice structure alters the working potential. More importantly, a dynamic equilibrium between bulk electrode and electrolyte is eventually reached for H2O transport during the charge/discharge cycles, with the water activity serving as the key parameter determining the direction of water movement and the cycling stability.
Water of life: H2O at the electrolyte/electrode interface plays a key role in assisting Zn2+ diffusion from electrolytes to the bulk surface, while H2O in the lattice structure alters the working potential. A dynamic equilibrium between the bulk electrode and electrolyte is eventually established for H2O transport during the charge/discharge cycles.
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