Yttrium Vanadium Oxide-Poly(3,4-ethylenedioxythiophene) Composite Cathode Material for Aqueous Zinc-Ion Batteries

Entanglement Added to Cross-Linked Chains Enables Tough Gelatin-Based Hydrogel for Zn Metal Batteries

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 ─RC═N─, 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.

Organic Dye Molecule Intercalated Vanadium Oxygen Hydrate Enables High-Performance Aqueous Zinc-Ion Storage

Although the layered vanadium oxide-based materials have been considered to be one of the candidates for aqueous Zn-ion batteries (AZIBs), it still faces inevitable challenges of unsatisfactory capacities and sluggish kinetics because of strong electrostatic interactions between Zn-ions and structure lattice. This work addresses the strategy of pre-inserting guest materials to vanadium oxide cathode using different intercalants. To achieve this goal, the small organic dye molecules, methyl orange (MO), and methylene blue (MB) are proposed as the intercalants for vanadium oxygen hydrate (VOH). It has been demonstrated that use of these intercalants can facilitate reaction kinetics between Zn2+ and VOH, leading to an improvement of specific capacity (293 mAh g-1 at 0.3 A g-1 for MO-VOH and 311 mAh g-1 for MB-VOH) compared to VOH, a large enhancement of excellent energy density (237.1 Wh kg-1 for MO-VOH, 232.3 Wh kg-1 for MB-VOH), and a prolong lifespan operation at 3 A g-1 . The mechanism studies suggest that the weakened electrostatic interactions between the Zn-ions and V-O lattice after intercalating organic molecules contribute to boosting the electrochemical performance of AZIBs unveiled by charge density difference and binding energy.

Vanadium-Based Cathodic Materials of Aqueous Zn-Ion Battery for Superior-Performance with Prolonged-Life Cycle

Aqueous Zn-ion battery systems (AZIBs) have emerged as the most dependable solution, as demonstrated by successful systematic growth over the past few years. Cost effectivity, high performance and power density with prolonged life cycle are some major reason of the recent progress in AZIBs. Development of vanadium-based cathodic materials for AZIBs has appeared widely. This review contains a brief display of the basic facts and history of AZIBs. An insight section on zinc storage mechanism ramifications is given. A detailed discussion is conducted on features of high-performance and long life-time cathodes. Such features include design, modifications, electrochemical and cyclic performance, along with stability and zinc storage pathway of vanadium based cathodes from 2018 to 2022. Finally, this review outlines obstacles and opportunities with encouragement for gathering a strong conviction for future advancement in vanadium-based cathodes for AZIBs.

Organic Intercalation Induced Kinetic Enhancement of Vanadium Oxide Cathodes for Ultrahigh-Loading Aqueous Zinc-Ion Batteries

Vanadium-based oxides have attracted much attention because of their rich valences and adjustable structures. The high theoretical specific capacity contributed by the two-electron-transfer process (V5+ /V3+ ) makes it an ideal cathode material for aqueous zinc-ion batteries. However, slow diffusion kinetics and poor structural stability limit the application of vanadium-based oxides. Herein, a strategy for intercalating organic matter between vanadium-based oxide layers is proposed to attain high rate performance and long cycling life. The V3 O7 ·H2 O is synthesized in situ on the carbon cloth to form an open porous structure, which provides sufficient contact areas with electrolyte and facilitates zinc ion transport. On the molecular level, the added organic matter p-aminophenol (pAP) not only plays a supporting role in the V3 O7 ·H2 O layer, but also shows a regulatory effect on the V5+ /V4+ redox process due to the reducing functional group on pAP. The novel composite electrode with porous structure exhibits outstanding reversible specific capacity (386.7 mAh g-1 , 0.1 A g-1 ) at a high load of 6.5 mg cm-2 , and superior capacity retention of 80% at 3 A g-1 for 2100 cycles.

Methods for Characterizing Intercalation in Aqueous Zinc Ion Battery Cathodes: A Review

Aqueous zinc ion batteries have gained research attention as a safer, economical and more environmentally friendly alternative to lithium-ion batteries. Similar to lithium batteries, intercalation processes play an important role in the charge storage behaviour of aqueous zinc ion batteries, with the pre-intercalation of guest species in the cathode being also employed as a strategy to improve battery performance. In view of this, proving hypothesized mechanisms of intercalation, as well as rigorously characterizing intercalation processes in aqueous zinc ion batteries is crucial to achieve advances in battery performance. This review aims to evaluate the range of techniques commonly used to characterize intercalation in aqueous zinc ion battery cathodes, providing a perspective on the approaches that can be utilized to rigorously understand such intercalation processes.

Enhancing the kinetics of vanadium oxides via conducting polymer and metal ions co-intercalation for high-performance aqueous zinc-ions batteries

Aqueous zinc-ions batteries with low cost, reliable safety, high theoretical specific capacity and eco-friendliness have captured conspicuous attention in large-scale energy storage. However, the developed cathodes often suffer from low electrical conductivity and sluggish Zn²⁺ diffusion kinetics, which severely hampers the development of aqueous zinc-ions batteries. Herein, we successfully prepare Mg/PANI/V₂O₅•nH₂O (MPVO) nanosheets through conducting polymers (polyaniline) and metal ions (Mg²⁺) co-intercalated strategy and systematically explore its electrochemical performance as cathode materials for aqueous zinc-ion batteries. Benefitting from the synergistic effect of polyaniline and Mg²⁺ co-intercalated, the MPVO exhibits larger interlayer spacing and higher electrical conductivity than the single guest intercalation, which significantly enhances the electrochemical kinetics. As a consequence, the MPVO cathodes deliver superior specific capacity, rate capability and long-term cycling performance. Moreover, multiple characterizations and theoretical calculations are executed to expound the relevant mechanism.Therefore, this work provides a novel thought for the design of high-performance cathode materials for aqueous ZIBs.