Aqueous rechargeable zinc ion batteries (ARZIBs) is considered one of the most compelling candidates for grid-scale energy storage owing to their cost effectiveness, good safety, eco-friendliness, ...high output voltage, and high capacity. However, their practical applications are still largely limited by the undesirable cyclability and high-rate capability. Here, we report a discovery that using a small amount (2 vol%) of diethyl ether (Et2O) as the electrolyte additive could largely improve the performance of Zn–MnO2 batteries. The addition of Et2O yielded the first cycle coulombic efficiency of 95.6% at 50 mA/g, a high capacity of 115.9 mAh/g at 5 A/g and 97.7% retention of initial capacity after 4000 cycles, demonstrating an outstanding rate capability and cycling performance among the reported Mn-based zinc ions batteries in mild electrolyte. Ex-situ characterizations revealed that appropriate amount of Et2O molecules could effectively suppress the formation of Zn dendrites on Zn anode, which is the main mechanism for cyclability improvements.
Aqueous Zn–MnO2battery with 2 vol% diethyl ether (Et2O) electrolyte additive exhibited significantly improved cycling stability, especially at high rates. The improvement was attribute to the effective suppression of dendrite formation on Zn metal anodes. Display omitted
•Et2O as electrolyte additive successfully improves the coulombic efficiency of Zn–MnO2 battery.•A high capacity retention of 97.7% of the Zn–MnO2 with Et2O is achieved after 4000 cycles at 5 A/g.•The Zn–Zn symmetrical battery with Et2O electrolyte additive sustains for over 250 h at 0.2 mA/cm2.•The highly-polarized Et2O molecules preferably adsorb on Zn extrusions, suppressing dendrite formation.
Highlights
The 2.27-nm-thick hybridized quasi-2D structure of La
2
O
3
crystalline nanoparticles embedded in La
2
O
3
amorphous nanosheets (La
2
O
3
@NP-NS) exhibited a low overpotential of 310 mV at ...10 mA cm
−2
.
The mass activity of La
2
O
3
@NP-NS reached as high as 6666.7 A g
−1
at overpotential of 310 mV. Such a high mass activity was more than three orders of magnitude higher than that of benchmark IrO
2
(4.4 A g
−1
) and RuO
2
(2.05 A g
−1
) and five orders of magnitude higher than that of commercial La
2
O
3
(0.048 A g
−1
).
Electrochemical catalysts for oxygen evolution reaction are a critical component for many renewable energy applications. To improve their catalytic kinetics and mass activity are essential for sustainable industrial applications. Here, we report a rare-earth metal-based oxide electrocatalyst comprised of ultrathin amorphous La
2
O
3
nanosheets hybridized with uniform La
2
O
3
nanoparticles (La
2
O
3
@NP-NS). Significantly improved OER performance is observed from the nanosheets with a nanometer-scale thickness. The as-synthesized 2.27-nm La
2
O
3
@NP-NS exhibits excellent catalytic kinetics with an overpotential of 310 mV at 10 mA cm
−2
, a small Tafel slope of 43.1 mV dec
−1
, and electrochemical impedance of 38 Ω. More importantly, due to the ultrasmall thickness, its mass activity, and turnover frequency reach as high as 6666.7 A g
−1
and 5.79 s
−1
, respectively, at an overpotential of 310 mV. Such a high mass activity is more than three orders of magnitude higher than benchmark OER electrocatalysts, such as IrO
2
and RuO
2
. This work presents a sustainable approach toward the development of highly efficient electrocatalysts with largely reduced mass loading of precious elements.
The emergence of memristive behavior in amorphous–crystalline 2D oxide heterostructures, which are synthesized by atomic layer deposition (ALD) of a few‐nanometer amorphous Al2O3 layers onto ...atomically thin single‐crystalline ZnO nanosheets, is demonstrated. The conduction mechanism is identified based on classic oxygen vacancy conductive channels. ZnO nanosheets provide a 2D host for oxygen vacancies, while the amorphous Al2O3 facilitates the generation and stabilization of the oxygen vacancies. The conduction mechanism in the high‐resistance state follows Poole–Frenkel emission, and in the the low‐resistance state is fitted by the Mott–Gurney law. From the slope of the fitting curve, the mobility in the low‐resistance state is estimated to be ≈2400 cm2 V−1 s−1, which is the highest value reported in semiconductor oxides. When annealed at high temperature to eliminate oxygen vacancies, Al is doped into the ZnO nanosheet, and the memristive behavior disappears, further confirming the oxygen vacancies as being responsible for the memristive behavior. The 2D heterointerface offers opportunities for new design of high‐performance memristor devices.
The quasi‐2D heterostructure of atomically thin ZnO monocrystalline nanosheet/amorphous Al2O3 enables exotic memristive behavior, which is attributed to the generation of concentrated oxygen vacancies with a high mobility in the low‐resistance state. This discovery reveals a new route for tuning the electronic transport property by 2D heterostructuring.
A type of interesting immobilized supramolecular catalysts based on surfactant‐encapsulated polyoxometalates has been developed for oxidation reactions. Through a sol‐gel process with tetraethyl ...orthosilicate, hydroxyl‐terminated surfactant‐encapsulated polyoxometalate complexes have been covalently and uniformly bound to a silica matrix with unchanged complex structure. The formed hybrid catalysts possess a defined hydrophobic nano‐environment surrounding the inorganic clusters, which is conducive to compatibility between the polyoxometalate catalytic centres and organic substrates. The supramolecular synergy between substrate adsorption, reaction, and product desorption during the oxidation process has been found to have an obvious influence on the reaction kinetics, with the activity of the catalyst being greatly improved. The supramolecular catalysts performed effectively in the selective oxidation of several different kinds of organic compounds, such as alkenes, alcohols, and sulfides, and the main products were the corresponding epoxides, ketones, sulfoxides, and sulfones. More significantly, the catalyst could be easily recovered by simple filtration, and the catalytic activity was well retained for at least five cycles. Finally, the present strategy has proved to be a general route for the fabrication of supramolecular hybrid catalysts containing common polyoxometalates suitable for various purposes.
Supramolecular synergy catalysis: Supramolecular catalysts based on surfactant‐encapsulated polyoxometalates have been developed for the oxidation of alcohols, alkenes, and sulfides with high efficiency and selectivity (see picture). Supramolecular synergy during the reaction process has been found to play a very important role in influencing the kinetics of the reaction and improving the catalytic activity.
Photodynamic therapy (PDT) by near-infrared (NIR) irradiation is a promising technique for treating various cancers. Here, we reported the development of free-standing wafer-scale Au nanosheets (NSs) ...that exhibited an impressive PDT effect. The Au NSs were synthesized by ionic layer epitaxy at the air-water interface with a uniform thickness in the range from 2 to 8.5 nm. These Au NSs were found very effective in generating singlet oxygen under NIR irradiation. In vitro cellular study showed that the Au NSs had very low cytotoxicity and high PDT efficiency due to their uniform 2D morphology. Au NSs could kill cancer cells after 5 min NIR irradiation with little heat generation. This performance is comparable to using 10 times mass loading of Au nanoparticles (NPs). This work suggests that two-dimensional (2D) Au NSs could be a new type of biocompatible nanomaterial for PDT of cancer with an extraordinary photon conversion and cancer cell killing efficiency.
We report the experimental observation of the spin-wave moiré edge and cavity modes using Brillouin light scattering spectromicroscopy in a nanostructured magnetic moiré lattice consisting of two ...twisted triangle antidot lattices based on an yttrium iron garnet thin film. Spin-wave moiré edge modes are detected at an optimal twist angle and with a selective excitation frequency. At a given twist angle, the magnetic field acts as an additional degree of freedom for tuning the chiral behavior of the magnon edge modes. Micromagnetic simulations indicate that the edge modes emerge within the original magnonic band gap and at the intersection between a mini flatband and a propagation magnon branch. Our theoretical estimate for the Berry curvature of the magnon-magnon coupling suggests a nontrivial topology for the chiral edge modes and confirms the key role played by the dipolar interaction. Our findings shed light on the topological nature of the magnon edge mode for emergent moiré magnonics.
A cationic dendritic molecule that has alkyl chains has been synthesized and employed to encapsulate anionic polyoxometalates through electrostatic interactions. The prepared surfactant‐encapsulated ...polyoxometalate (SEP) complexes were used as building blocks to fabricate self‐assemblies in solution and the solid state. Monodispersion, lamellar, and columnar assemblies of SEP complexes have been characterized in detail. With increasing the number of peripheral cationic dendrons on inorganic clusters, the SEPs undergo changes from globular assemblies to monodispersions in solution and from lamellar assemblies to hexagonal columnar structures in the solid state, depending on the amounts of cationic dendrons in the complexes. The structural evolvement was simulated through consideration of the size and shape of the cationic dendron and polyanionic clusters, and the experimental results are in good agreement with the interpretation of the simulations. The present research demonstrates a new kind of dendritic complex and provides a route for controlling their assembling states by simply alternating the number of cationic dendrons in the complexes.
Structural controlling: Dendritic surfactant‐encapsulated polyoxometalate complexes with different numbers of dendrons have been prepared. On increasing the number of dendrons, the complex dendrimers change from globular assembled states to monodispersions in solution and from lamellar to hexagonal columnar structures in the solid state (see graphic).
A series of cationic dendrons bearing triethylene glycol monomethyl ether terminal groups of different generations have been synthesized and used to encapsulate an inorganic polyanionic cluster ...K12.5Na1.5(NaP5W30O110) through electrostatic interactions. The resulting dendritic cation–encapsulated polyoxometalate (POM) complexes, cluster–dendrimers, are soluble in water and exhibit lower critical solution temperatures (LCST). The thermoresponsivities of these complexes in aqueous solutions were studied by turbidimetry and variable‐temperature 1H NMR spectroscopy. The observed cloud points show a remarkable dependence on the generation of the dendrons. Complexes composed of first‐generation dendrons exhibit no obvious thermoresponsive properties, but for complexes bearing second‐generation dendrons, the LCST decreases as the number of dendritic cations around the POM cluster increases. Complexes composed of third‐generation cations underwent reversible aggregation and disaggregation upon heating and cooling, respectively. This thermally induced self‐aggregation was characterized by DLS and TEM. In addition, the effects of salt and solvent on the LCST were investigated. This research demonstrates a new type of thermoresponsive dendritic organic–inorganic hybrid complex and provides a general route to the endowment of POMs with temperature‐sensitive properties through electrostatic interactions.
Thermoresponsive dendrimers: A series of cationic dendrons with glycol terminal groups have been used to encapsulate a typical polyoxometalate polyanion through electrostatic interactions to obtain a new type of hybrid dendrimer complex. An increase in the generation of the dendrons leads to a dramatic aggregation transition at a lower critical solution temperature, which can be modulated by salts and solvent (see figure).
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