Water‐in‐salt (WiS) electrolytes provide a new pathway to widen the electrochemical window of aqueous electrolytes. However, their formulation strongly depends on the solubility of the chosen salts, imposing a stringent restriction on the number of possible WiS systems. This issue becomes more severe for aqueous Na‐ion batteries (ANIBs) owing to the relatively lower solubility of sodium salts compared to its alkaline cousins (Li, K, and Cs). A new class of the inert‐cation‐assisted WiS (IC‐WiS) electrolytes containing the tetraethylammonium (TEA+) inert cation is reported. The Na IC‐WiS electrolyte at a superhigh concentration of 31 mol kg–1 exhibits a wide electrochemical window of 3.3 V, suppresses transition metal dissolution from the cathode, and ensures singular intercalation of Na into both cathode and anode electrodes during cycling, which is often problematic in mixed alkali cation systems such as K–Na and Li–Na. Owing to these unique advantages of the IC‐WiS electrolyte, the NaTiOPO4 anode and Prussian blue analog Na1.88Mn[Fe(CN)6]0.97·1.35H2O cathode can be coupled to construct a full ANIB, delivering an average voltage of 1.74 V and a high energy density of 71 Wh kg−1 with a capacity retention of 90% after 200 cycles at 0.25C and of 76% over 800 cycles at 1C.

Home quarantine may lead to families developing a variety of psychological distress. The purpose of this study was to examine the psychological status of children and their parent during 2019 coronavirus disease (COVID-19) outbreak in China. Data were collected from children ( n = 1360) and their parent ( n = 1360) in China using online survey during February 2020. Demographic information, media exposure, and psychological status including anxiety, depression and posttraumatic stress disorder (PTSD) symptoms were assessed using self-report measures. The results indicated that, for children, 1.84% experienced moderate anxiety, 2.22% experienced depression and 3.16% met the diagnostic criteria for PTSD; for parent, 1.18%, 0.01% and 3.60% experienced moderate anxiety, severe depression, and moderate depression, respectively, and 3.53% met the diagnostic criteria for PTSD. Moreover, excessive media exposure ( β = −0.08 ~ 0.13, p s < 0.05) was a risk factor for anxiety and PTSD for children, a positive factor against anxiety and depression for parent. Being a mother ( β = 0.07 ~ 0.21, p s < 0.01), being younger ( β = −0.09 ~ −0.07, p s < 0.05), lower levels of educational attainment ( β = −0.17 ~ −0.08, p s < 0.01) and family monthly income ( β = −0.17 ~ −0.11, p s < 0.05) were risk factors for anxiety, depression and PTSD for parent. Findings suggested that children and their parent in non-severe area didn’t suffer major psychological distress during the outbreak. Factors associated with lower levels of mental health problems were identified to inform the use of psychological interventions to improve the mental health of vulnerable groups during the pandemic.

The lack of high-power and stable cathodes prohibits the development of rechargeable metal (Na, Mg, Al) batteries.Herein, poly(hexaazatrinaphthalene)(PHATN), an environmentally benign, abundant and sustainable polymer, is employed as auniversal cathode material for these batteries. In Na-ion batteries (NIBs), PHATN delivers ar eversible capacity of 220 mAh g À1 at 50 mA g À1 ,c orresponding to the energy density of 440 Wh kg À1 ,and still retains 100 mAh g À1 at 10 Ag À1 after 50 000 cycles,w hich is among the best performances in NIBs.S uch an exceptional performance is also observed in more challenging Mg and Al batteries.P HATN retains reversible capacities of 110 mAh g À1 after 200 cycles in Mg batteries and 92 mAh g À1 after 100 cycles in Al batteries. DFT calculations,X -ray photoelectron spectroscopy, Raman, and FTIR showt hat the electron-deficient pyrazine sites in PHATN are the redoxc enters to reversibly react with metal ions.

Owing to its unique structure, Chevrel phase (CP) is a promising candidate for applications in rechargeable multivalent (Mg and Al) batteries. However, its wide applications are severely limited by time-consuming and complex synthesis processes, accompanied by uncontrollable growth and large particle sizes, which will magnify the charge trapping effect and lower the electrochemical performance. Here, an iodine vapor transport reaction (IVT) is proposed to obtain large-scale and highly pure Mo6S8 nanosheets, in which iodine helps to regulate the growth kinetics and induce the preferential growth of Mo6S8, as a typical three-dimensional material, to form nanosheets. When applied in rechargeable multivalent (Mg and Al) batteries, Mo6S8 nanosheets show very fast kinetics owing to the short diffusion distance, thereby exhibiting lower polarization, higher capacities, and better low-temperature performance (up to −40 °C) compared to that of microparticles obtained via the conventional method. It is anticipated that Mo6S8 nanosheets would boost the application of Chevrel phase, especially in areas of energy storage and catalysis, and the IVT reaction would be generalized to a wide range of inorganic compound nanosheets.

Mass dissolution is one main problems for cathodes in aqueous electrolytes due to the strong polarity of water molecules. In principle, mass dissolution is a thermodynamically favorable process as determined by the Gibbs free energy. However, in real situations, dissolution kinetics, which include viscosity, dissolving mass mobility, and interface properties, are also a critical factor influencing the dissolution rate. Both thermodynamic and kinetic dissolving factors can be regulated by the ratio of salt to solvent in the electrolyte. In this study, concentration‐controlled cathode dissolution is investigated in a susceptible Na3V2(PO4)3 cathode whose time‐, cycle‐, and state‐of‐charge‐dependent dissolubility are evaluated by multiple electrochemical and chemical methods. It is verified that the super‐highly concentrated water‐in‐salt electrolyte has a high viscosity, low vanadium ion diffusion, low polarity of solvated water, and scarce solute−water dissolving surfaces. These factors significantly lower the thermodynamic‐controlled solubility and the dissolving kinetics via time and physical space local mass interfacial confinement, thereby inducing a new mechanism of interface concentrated‐confinement which improves the cycling stability in real aqueous rechargeable sodium‐ion batteries.

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Prussian blue analogues (PBAs) are considered to be ideal multivalent cation host materials due to their unique open-framework structure. In aqueous solution, however, the PBAs’ cathodes have a low reversible capacity limited by the single electrochemical group Fe­(CN)6 3– and high crystal water content. They also suffer from fast cycle fading, resulting from significant oxygen/hydrogen evolution and cathode dissolution. In this work, a high-capacity PBA-type FeFe­(CN)6 cathode with double transition metal redox sites is successfully demonstrated in 5 m Al­(CF3SO3)3 Water-in-Salt electrolyte (Al-WISE). Due to Al-WISE having a wide electrochemical window (2.65 V) and low dissolution of the cathode, our PBA cathode exhibits a high discharge capacity of 116 mAh/g and the superior cycle stability >100 cycles with capacity fading of 0.39% per cycle.

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