RESUMO
Currently, it is still challenging to develop a hydrogel electrolyte matrix that can successfully achieve a harmonious combination of mechanical strength, ionic conductivity, and interfacial adaptability. Herein, a multi-networked hydrogel electrolyte with a high entanglement effect based on gelatin/oxidized dextran/methacrylic anhydride, denoted as ODGelMA is constructed. Attribute to the Schiff base network formulation of âRCâNâ, oxidized dextran integrated gelatin chains induce a dense hydrophilic conformation group. Furthermore, addition of methacrylic anhydride through a grafting process, the entangled hydrogel achieves impressive mechanical features (6.8 MPa tensile strength) and high ionic conductivity (3.68 mS cm-1 at 20 °C). The ODGelMA electrolyte regulates the zinc electrode by circumventing dendrite growth, and showcases an adaptable framework reservoir to accelerate the Zn2+ desolvation process. Benefiting from the entanglement effect, the Zn anode achieves an outstanding average Coulombic efficiency (CE) of 99.8% over 500 cycles and cycling stability of 900 h at 5 mA cm-2 and 2.5 mAh cm-2. The Zn||I2 full cell yields an ultra-long cycling stability of 10 000 cycles with a capacity retention of 92.4% at 5 C. Furthermore, a 60 mAh single-layer pouch cell maintains a stable work of 350 cycles.
RESUMO
The development of metal ion-intercalated active materials for excellent electrochemical performance in rechargeable aqueous zinc-ion batteries (AZIBs) is challenging. The structure instability and intrinsic electrostatic repulsion of the lattice framework cause structural breakdown and low-rate performance. In response to these problems, yttrium vanadium oxide-poly(3,4-ethylenedioxythiophene) (PEDOT@YVO) composite is reported as stable cathode material for AZIBs. The introduction of PEDOT in YVO nanorods improves the crystalline structure with an enlarged interplanar lattice spacing of 3.4 Å. The PEDOT@YVO composite electrode demonstrates effective electric conductivity and a higher initial specific capacity of 308.5 mAh g-1 than that (125.5 mAh g-1 ) of the pure YVO at 0.2 C rate. It also features a long-term stable discharge-charge cycle performance of 4000 cycles with a capacity retention of 79.2% at 1C rate, better than YVO (29.4 mAh g-1 ). The oxygen vacancies and improved electrical conductivity of the composite account for the invigorated electrochemical performance. Consequently, this work reveals another avenue for constructing unique electrodes to enhance the electrochemical properties of AZIBs.
RESUMO
Conventional organic batteries suffer from rapid capacity fading. Organic compounds are inclined to dissolve in the electrolyte and limit the long-term cycling performance of lithium-organic batteries. Carbon skeletons show efficacy in confining the active materials of organic cathodes. In this study, we investigate the electrochemical performance of aqueous zinc-ion batteries with binder-free composite cathodes consisting of carbon nanotubes (CNTs) and naphthoquinone (NQ)-based organics. The quinones are trapped in the nanoporous structure of the CNT framework, and thus the dissolution was minimized. The composite cathodes show stable and high rate cyclability, owing to the high electrical conductivity and confinement of the CNT network. The NQ composite cathode exhibits an initial capacity of 333.5 mAh g-1, close to the theoretical capacity of 339.0 mAh g-1. Furthermore, it is uncovered that modifying NQ with functional groups significantly impacts the electrochemical behavior, including the redox potential and capacity retention. With the electron-withdrawing or electron-donating groups, dichlone and 2-((4-hydroxyphenyl) amino) naphthalene-1,4-dione (APh-NQ) show better performance than NQ with improved capacity retention from 41.0 to 70.9 and 68.3%, respectively, after 1000 cycles. The work promotes the development of binder-free organic cathodes for the aqueous Zn-ion batteries and sheds light on designing high-performance electrodes for low-cost energy storage systems.
