Conventional aqueous batteries usually suffer from serious capacity loss under subzero conditions owing to the freeze of electrolytes. To realize the utilization of aqueous batteries in extremely cold climates, low-temperature aqueous battery systems have to be developed. Herein, an aqueous Pbquinone battery based on p-chloranil/reduced graphene oxide (PCHL-rGO) in H 2 SO 4 electrolyte is developed. Such aqueous Pb/PCHL-rGO batteries display H + insertion chemistry, which endows the batteries with fast reaction kinetics and high rate capability. In addition, the hydrogen bonds between water molecules can be significantly damaged in electrolyte by modulating the interaction between SO 4 2À and water molecules, lowering the freezing point of electrolyte. As a result, the Pb/ PCHL-rGO batteries deliver extraordinary electrochemical performance even at À70 8C. This work will broaden the horizons of aqueous batteries and open up new opportunities to construct low-temperature aqueous batteries.

Lithium ion batteries have proven themselves the main choice of power sources for portable electronics. Besides consumer electronics, lithium ion batteries are also growing in popularity for military, electric vehicle, and aerospace applications. The present review attempts to summarize the knowledge about some selected membranes in lithium ion batteries. Based on the type of electrolyte used, literature concerning ceramic-glass and polymer solid ion conductors, microporous filter type separators and polymer gel based membranes is reviewed.

Aqueous zinc‐ion batteries (ZIBs) with low cost and high safety are promising energy‐storage devices. However, ZIBs with metal Zn anodes usually suffer from low coulombic efficiency and poor cycling performance due to the occurrence of side reactions on the Zn anodes. Here, a binary hydrate‐melt ZnCl2/Zn(OAc)2 electrolyte is designed to suppress the hydrogen evolution reaction and by‐product formation on Zn anodes by adjusting the Zn2+ solvation structure. In the solvation structure of the hydrate‐melt ZnCl2/Zn(OAc)2 electrolyte, the carboxylate group in OAc− will coordinate with the Zn2+, which will weaken the interaction between Zn2+ and H2O molecules to achieve higher ionization energy of H2O molecules. Simultaneously, these carboxylate groups of OAc− can serve as H‐bond acceptors to construct H‐bonds with H2O molecules in their neighboring solvation structures, forming a cross‐linking H‐bond network. Such a cross‐linking H‐bond network further suppresses the water activity in ZnCl2/Zn(OAc)2 electrolyte. As a result, in such an electrolyte, the side reactions are effectively restricted on Zn anodes and thus Zn anodes can achieve a high coulombic efficiency of 99.59% even after cycling. To illustrate the feasibility of the ZnCl2/Zn(OAc)2 electrolyte in aqueous ZIBs, Zn||p‐chloranil cells are assembled based on the ZnCl2/Zn(OAc)2 electrolyte. The resultant Zn||p‐chloranil cells exhibit enhanced cycling performance compared with the cases with a conventional ZnSO4 electrolyte.

The direct ethanol fuel cells in an alkaline medium have a broad vision of applications because of their large energy density, reasonable power density, and environmentally friendly features. Herein, we present a facile one-step method to synthesize PdAg nanosheet assemblies (NSAs) in a mixed solution of N,Ndimethylformamide and water with the addition of molybdenum hexacarbonyl and cetyltrimethylammonium bromide. Pure Pd NSA shows an irregular shape while PdAg NSAs gradually undergo a process from solid assembly to a hollow structure with the Pd/Ag molar ratio changing from 3:1 to 2:1 to 1:1. The formation of alloy nanosheets in the assemblies combined with the introduction of Ag in the Pd catalyst enhances the catalytic activity toward ethanol electrooxidation from 1524 mA mg −1 of pure Pd NSA to 1866 mA mg −1 of PdAg NSA with a Pd/Ag molar ratio of 2:1. On the basis of the experimental data, compared with pure Pd structures, both the nature of a thin nanosheet of PdAg NSAs and the structural changes in the alloy assemblies play key roles in determining the electrocatalytic activity of these Pd-based catalysts.

Microbial fuel cells (MFCs) are devices that use bacteria as the catalysts to oxidize organic and inorganic matter and generate current whereas microbial electrolysis cells (MECs) are a reactor for biohydrogen production by combining MFC and electrolysis. In an MEC, an external voltage must be applied to overcome the thermodynamic barrier. Here we report an MEC-MFC-coupled system for biohydrogen production from acetate, in which hydrogen was produced in an MEC and the extra power was supplied by an MFC. In this coupled system, hydrogen was produced from acetate without external electric power supply. At 10 mM of phosphate buffer, the hydrogen production rate reached 2.2 +/- 0.2 mL L(-1) d(-1), the cathodic hydrogen recovery (RH2) and overall systemic Coulombic efficiency (CEsys) were 88 to approximately 96% and 28 to approximately 33%, respectively, and the overall systemic hydrogen yield (Y(sysH2)) peaked at 1.21 mol-H2 mol-acetate(-1). The hydrogen production was elevated by increasing the phosphate buffer concentration, and the highest hydrogen production rate of 14.9 +/- 0.4 mL L(-1) d(-1) and Y(sysH2) of 1.60 +/- 0.08 mol-H2 mol-acetate(-1) were achieved at 100 mM of phosphate buffer. The performance of the MEC and the MFC was influenced by each other. This MEC-MFC-coupled system has a potential for biohydrogen production from wastes, and provides an effective way for in situ utilization of the power generated from MFCs.

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The molecular recoiling force stemming from nonequilibrium chain conformation was found to play a very important role in the dewetting stability of polymer thin films. Correct measurements and inclusion of this molecular force into thermodynamic consideration are crucial for analyzing dewetting phenomena and nanoscale polymer chain physics. This force was measured using a simple method based on contour relaxation at the incipient dewetting holes. The recoiling stress was found to increase dramatically with molecular weight and decreasing film thickness. The corresponding forces were calculated to be in the range from 9.0 to 28.2 mN/m, too large to be neglected when compared to the dispersive forces (approximately 10 mN/m) commonly operative in thin polymer films.