Search

Zn metal anode suffers from dendrite issues and passive byproducts, which severely plagues the practical application of aqueous Zn metal batteries. Herein, a polyzwitterionic cross-linked double network hydrogel electrolyte composed of physical crosslinking (hyaluronic acid) and chemical crosslinking (synthetic zwitterionic monomer copolymerized with acrylamide) is introduced to overcome these obstacles. On the one hand, highly hydrophilic physical network provides an energy dissipation channel to buffer stress and builds a H2O-poor interface to avoid side reactions. On the other hand, the charged groups (sulfonic and imidazolyl) in chemical crosslinking structure build anion/cation transport channels to boost ions' kinetics migration and regulate the typical solvent structure [Zn(H2O)6]2+ to R-SO3− [Zn(H2O)4]2+, with uniform electric field distribution and significant resistance to dendrites and parasitic reactions. Based on the above functions, the symmetric zinc cell exhibits superior cycle stability for more than 420 h at a high current density of 5 mA·cm−2, and Zn∥MnO2 full cell has a reversible specific capacity of 150 mAh·g−1 after 1000 cycles at 2 C with this hydrogel electrolyte. Furthermore, the pouch cell delivers impressive flexibility and cyclability for energy-storage applications. [ABSTRACT FROM AUTHOR]

Polymer electrolytes provide a visible pathway for the construction of high‐safety quasi‐solid‐state batteries due to their high interface compatibility and processability. Nevertheless, sluggish ion transfer at room temperature seriously limits their applications. Herein, a triangular synergy strategy is proposed to accelerate Na‐ion conduction via the cooperation of polymer‐salt, ionic liquid, and electron‐rich additive. Especially, PVDF‐HFP and NaTFSI salt acted as the framework to stably accommodate all the ingredients. An ionic liquid (Emim+‐FSI−) softened the polymer chains through a weakening molecule force and offered additional liquid pathways for ion transport. Physicochemical characterizations and theoretical calculations demonstrated that electron‐rich Nerolin with π‐cation interaction facilitated the dissociation of NaTFSI and effectively restrained the competitive migration of large cations from EmimFSI, thus lowering the energy barrier for ion transport. The strategy resulted in a thin F‐rich interphase dominated by NaTFSI salt's decomposition, enabling rapid Na+ transmission across the interface. These combined effects resulted in a polymer electrolyte with high ionic conductivity (1.37×10−3 S cm−1) and tNa+ (0.79) at 25 °C. The assembled cells delivered reliable rate capability and stability (200 cycles, 99.2 %, 0.5 C) with a good safety performance. [ABSTRACT FROM AUTHOR]