Search

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]

SnS2 has a large volume change and unstable structure during charging and discharging, seriously hindering its application in lithium‐ion batteries (LIBs) and sodium‐ion batteries (SIBs). Herein, ultrafine nanocrystals SnS2 are confined to the inner wall of hollow mesoporous carbon nanospheres (HMCNS) by one‐step hydrothermal reaction for the first time, forming a special hollow structure with buffer volume effect. After a series of electrochemical analyses, the composite not only displays preeminent long cyclic stability and excellent rate performance, but also shows a hybrid storage mechanism. When used as the anode for LIBs, SnS2@HMCNS maintains a superior capacity of 755 mAh g−1 after 100 cycles at 0.1 A g−1 and at 2 A g−1, the capacity is 547.8 mAh g−1. Besides, adopted as the anode of SIBs, SnS2@HMCNS exhibits a capacity of 254.5 mAh g−1 after 1000 cycles at 1 A g−1, far exceeding that of pure SnS2. The outstanding electrochemical performance is owed to the ultrafine nanocrystals SnS2 adhered to the inner wall of HMCNS, which prevents stacking and increases the active lithium/sodium storage sites. Additionally, the large cavity of HMCNS can provide sufficient buffer space for SnS2 in the process of ion embedding/stripping, optimizing the structural stability of the composite. [ABSTRACT FROM AUTHOR]

Dibenzo-18-crown-6 (DB18C6) as a host compound was doped into polyacrylonitrile (PAN) solution. The composite nanofibers (DB18C6/PAN) were prepared by the electrospinning. The morphology, chemical structure and thermal stability of nanofibers were characterized by field emission scanning electron microscope (FE-SEM), Fourier transform infrared spectroscopy (FT-IR), and thermal gravimetric analysis (TGA), respectively. The composite nanofibers with good morphology were obtained by controlling the weight percent of DB18C6 and electrospinning parameters. The static adsorption behavior of alkali metal ions and alkaline earth metal ions of different proportional DB18C6/PAN nanofibers were studied. DB18C6/PAN nanofibers have adsorptive selectivity about alkali metal ions: K+ > Na+ > > Cs+ > Li+. The 15wt%DB18C6/PAN nanofibers have the highest adsorption capacity. The adsorption kinetics of 15wt%DB18C6/PAN nanofibers for Na+ and K+ were accorded with the first-order equation, and the adsorption rate constants were 9.5 × 10–3 min−1 and 1.5 × 10–2 min−1, respectively. At 25 °C, the isotherm adsorption of the DB18C6/PAN nanofibers for Na+ and K+ was confirmed to the Langmuir adsorption isotherm, and the maximum adsorption quantities of 15wt%DB18C6/PAN nanofibers were 11.9 mg g−1 and 24.8 mg g−1, respectively. [ABSTRACT FROM AUTHOR]

The amorphous ZrF layer with various concentrations coated Li[LiMnNiCo]O cathodes were synthesized by using the chemical deposition technology. The combinations of XRD, SEM and TEM results indicated that the nanoparticles ZrF layer was successfully covered on the surface of the Li[LiMnNiCo]O particles. Compared to the pristine Li[LiMnNiCo]O, the cathodes after ZrF coating demonstrated the obviously enhanced electrochemical properties. The 2 wt% ZrF-coated Li[LiMnNiCo]O delivered a high capacity retention of 91.9% after 100 cycles at 0.5 C, much higher than that (84.5%) of the uncoated sample. Besides, the discharge capacity of 2 wt% ZrF-coated Li[LiMnNiCo]O was approximately 20.0 mAh g larger than that of the pristine Li[MnNiCo]O at various current densities. The EIS analysis indicated the remarkably enhanced electrochemical properties of the surface-modified electrode was ascribed to the fact that the ZrF coating layer could restrict the side reaction between cathodes with electrolyte and protect the cathode surface from HF corrosion, further accelerate the Li diffusion rate in the cathode. [ABSTRACT FROM AUTHOR]

A microporous carbon coated core/shell Si@C nanocomposite prepared by in situpolymerization exhibits a stable capacity of over 1200 mAh g−1with 95.6% retention even after 40 cycles, which makes it a promising anode material for lithium ion batteries. [ABSTRACT FROM AUTHOR]