Overcoming Challenges: Extending Cycle Life of Aqueous Zinc-Ion Batteries at High Zinc Utilization through a Synergistic Strategy

Rationally Engineering a Quasi-Solid-State Flexible Self-Healing Secondary Battery Using Hydrogel-Based Water-in-Salt Electrolyte and Electrochemically Deposited Electrodes

High safety and low cost are essential for energy-storage systems. Here, an aqueous zinc ion battery composed of a hydrogel-based water-in-salt electrolyte prepared by photoinitiated polymerization of acrylamide in ZnCl2 solution (named as PZC) and flexible electrodes is developed. The stable performance in Zn||Zn symmetric cells and high Coulombic efficiency of PZC in Zn||Cu asymmetric cells verify dendrite suppression. VO2 nanobelts coated with polyaniline (PANI) are grown on a carbon cloth (CC). The battery shows a capacity of 221.5 mAh g-1 after 200 cycles. The batteries present high recovery performance after bending/cutting. After bending of 60°, 90°, and 180°, capacities remain at 240.0, 205.4, and 175.2 mAh g-1, respectively; while the battery healed from 1, 2, 3, and 4 times of cutting shows 197.5, 174.3, 124.7, and 101.2 mAh g-1, respectively. Our findings enable the engineering of a quasi-solid-state battery to have good capability for flexible and portable electronics.

Layered S-Bridged Covalent Triazine Frameworks via a Bifunctional Template-Catalytic Strategy Enabling High-Performance Zinc-Ion Hybrid Supercapacitors

Exploring covalent triazine frameworks (CTFs) with high capacitative activity is highly desirable and challenging. Herein, the S-rich CTFs cathode is pioneeringly introduced in Zn-ion hybrid supercapacitors (ZSC), achieving outstanding capacity and energy density, and satisfactory anti-freezing flexibility. Specifically, the S-bridged CTFs are synthesized by a bifunctional template-catalytic strategy, where ZnCl2 serves as both the catalyst/solvent and in situ template to construct triazine frameworks with interconnected pores and layered gaps. The resultant CTFs (CTFS-750) are employed as a reasonable pattern-like system to more deeply scrutinize the synergistic effect of S-bridged triazine and layered porous architecture for polymer-based cathodes in Zn-ion storage. The experimental results indicate that the adsorption barriers of Zn-ions on CTFS-750 are effectively weakened, and accessible Zn2+-absorption sites provided by the C─S─C and C═N bonds have been confirmed via DFT calculations. Consequently, the CTFS-750 cathode-assembled ZSC displays an ultra-high capacity of 211.6 mAh g-1 at 1.0 A g-1, an outstanding energy density of 202.7 Wh kg-1, and attractive cycling performance. Moreover, the resulting flexible ZSC device shows superior capacity, good adaptability, and satisfactory anti-freezing behavior. This approach sheds new light on constructing advanced polymer-based cathodes at the atom level and paves the way for fabricating high-performance ZSC and beyond.