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Aqueous rechargeable batteries (ARBs) are generally safer than non-aqueous analogues, they are also less-expensive, and more friendly to the environment. However, the inherent disadvantage of the narrow electrochemical window of H2O seriously restricts the energy density and output voltage of ARBs, especially aqueous rechargeable Fe-based batteries. Herein, we introduce a new battery system: the anode contains C@Fe/Fe2O3 composite, which is interfaced with an alkaline electrolyte; the cathode contains LiMn2O4 in contact with a neutral electrolyte. A Li+-conducting membrane is carefully selected to decouple the electrode-electrolyte, which effectively widens the electrochemical window to above 2.65 V, thereby enables an aqueous rechargeable iron battery. Its average output voltage is 1.83 V and its energy density is 235.3 Wh/kg at 549 W/kg. In this work, we propose the energy storage mechanism with the aid of density functional theory (DFT). The calculated reduction potential of the anode agrees with the experimental value. Furthermore, this battery system demonstrates long cycle lifespan of approximately 2500 cycles at 2 A/g, corresponding to a capacity retention of 82.1%. These results are very far superior than those of mainstream aqueous rechargeable Fe-based batteries, which guarantee future investigation for storing electricity energy. [ABSTRACT FROM AUTHOR]

Zinc corrosion and dendrite formation are the main issues which impede the performance of aqueous zinc ion batteries (ZIBs) after certain times. In this work, we systematically investigated the effects of three different valence ions (e. g. Na+, Mg2+, Al3+) as electrolyte additives on the suppression of zinc corrosion and the inhibition of dendrite growth. By combining experiments and theoretical calculations, it has been found that the existence of Na+ ions effectively suppressing the zinc dendrite growth because Na+ possessess high adsorption energy approximately −0.39 eV. Moreover, Na+ ions could lengthen the zinc dendrite formation duration up to 500 h. On the other hand, the PANI/ZMO cathode materials showed the small band gap approximately 0.097 eV, signifying that the PANI/ZMO possessed the semiconductor characteristics. Furthermore, an assembled Zn//PANI/ZMO/GNP full battery using Na+ ions as electrolyte additive displayed capacity retention of 90.2 % after 500 cycles at 0.2 A g−1, whereas the capacity retention of the control battery using pure ZnSO4 electrolyte was only 58.2 %. This work could provide a reference for the selection of electrolyte additives in future batteries. [ABSTRACT FROM AUTHOR]

Three major components in a cathode of aqueous rechargeable lithium batteries are the active material, the polymer binder, and the carbon conductive additive. The stability of each component in the battery is the key to long service life. To evaluate the stability of the carbon component, we introduce here a quick and direct testing method. LiMn2O4 is chosen as a typical active material for the preparation of the cathode, with polyvinylidene fluoride (PVdF), and a commercial carbon, which is chosen among Acetylene black, superP, superP-Li, Ketjen black 1, Ketjen black 2, Graphite, KS-6, splintered glassy carbon, and splintered spherical carbon. This method reveals the correlation between the electrochemical stability of a carbon and its physical and structural properties. This helps researchers choose the right carbon component for a Li-ion cathode if they want the battery to be robust, especially at near full state of charge. [ABSTRACT FROM AUTHOR]

The morphology of methylammonium lead iodide MAPbI3, formed by a two-step method with non-stoichiometric, excessive PbI2 concentration for a high carrier lifetime is reported. Through this excessive PbI2 alteration, the morphology, crystallinity, and carrier lifetime are purposely optimized. When the PbI2 concentration was 0.5 g ml−1, the nanotubes started to appear and were mixed with perovskite thin film, which yielded a significant average value of an effective carrier lifetime of 14.1 μs, resulting from the microwave photoconductivity decay on the perovskite prepared from the optimized method. The local value of effective carrier lifetime even reached above 60 μs at several locations. When the PbI2 concentration reached 0.6 g ml−1, synthetic perovskites contained bundles of nanotubes. This study provides a new framework for optimizing perovskites with appropriate surplus PbI2 and offers a scalable pathway for fabricating the perovskite material for best solar conversion efficiency. [ABSTRACT FROM AUTHOR]

Abstract: The synthesis of novel zinc electrodes has been successfully implemented by using the electroplating method with the aid of inorganic additives in the electroplating solution. The selected inorganic additives are indium sulfate, tin oxide, and boric acid. From X‐ray diffraction results, these synthesized zinc electrodes prefer (002) and/or (103) crystallographic orientations, representing basal morphology and high resistance to dendrite growth. The corrosion rates of these electroplated zinc samples decrease as much as 11 times smaller than the corrosion rate on zinc foil when the zinc materials are in contact with the aqueous electrolyte of a rechargeable hybrid aqueous battery (ReHAB). The ReHABs employing these anodes exhibit up to a threefold decrease in float charge current density after a seven‐day constant‐voltage charging at 2.1 V versus Zn2+/Zn. Furthermore, the capacity retention is up to 15 % higher than the performance of battery containing commercial Zn after 1000 cycles of charge–discharge. The significant advancements are attributed to the careful preparation of the anode, which contains appropriate crystallographic orientation and morphology. [ABSTRACT FROM AUTHOR]

Novel carbon materials, carbon nanotubes (CNTs) and porous graphene (PG), were exploited and used as conductive additives to improve the rate performance of LiMn2O4 cathode for the rechargeable aqueous Zn/LiMn2O4 battery, namely the rechargeable hybrid aqueous battery (ReHAB). Thanks to the long-range conductivity and stable conductive network provided by CNTs, the rate and cycling performances of LiMn2O4 cathode in ReHAB are highly improved-up to about 100 mAh.g-1 capacity is observed at 10 C (1 C = 120 mAh.g-1). Except for CNTs, porous graphene (PG) with a high surface area, an abundant porous structure, and an excellent electrical conductivity facilitates the transportation of Li ions and electrons, which can also obviously enhance the rate capability of the ReHAB. This is important because the ReHAB could be charged/discharged in a few minutes, and this leads to potential application of the ReHAB in automobile industry. [ABSTRACT FROM AUTHOR]

The Zn anode in secondary aqueous batteries suffers from dendrite formation and corrosion. In this work, dendrite formation was suppressed by using a simple but new gel electrolyte containing fumed silica and an additive. The dendrite suppression was evidenced by chronoamperometry and ex situ scanning electron microscopy examinations. Pyrazole was implemented as the additive in the electrolyte. It was found that the presence of 0.2 wt % pyrazole in the electrolyte helped minimize both corrosion and dendrite formation. The Zn/LiMn2O4 battery using pyrazole-containing gel electrolytes exhibited high cyclability up to 85 % capacity retention after 500 charge-discharge cycles at 4C. This was 8 % higher than the performance of the reference battery (using aqueous electrolyte containing 2 m Li2SO4 and 1 m ZnSO4). Furthermore, self-discharge of the battery with the pyrazole-containing gel electrolyte was suppressed, as evidenced by an open-circuit voltage loss that was 20 % lower than for the reference battery after 24 h monitoring. Float-charge current density under constant voltage (2.1 V) also significantly decreased from approximately 8.0 to 3-6 μA. [ABSTRACT FROM AUTHOR]