Amino-Functionalized Interfacial Layer Enables an Ultra-Uniform Amorphous Solid Electrolyte Interphase for High-Performance Aqueous Zinc-Based Batteries

Stable Zinc Anode Facilitated by Regenerated Silk Fibroin-modified Hydrogel Protective Layer

Inherent dendrite growth and side reactions of zinc anode caused by its unstable interface in aqueous electrolytes severely limit the practical applications of zinc-ion batteries (ZIBs). To overcome these challenges, a protective layer for Zn anode inspired by cytomembrane structure is developed with PVA as framework and silk fibroin gel suspension (SFs) as modifier. This PVA/SFs gel-like layer exerts similar to the solid electrolyte interphase, optimizing the anode-electrolyte interface and Zn2+ solvation structure. Through interface improvement, controlled Zn2+ migration/diffusion, and desolvation, this buffer layer effectively inhibits dendrite growth and side reactions. The additional SFs provide functional improvement and better interaction with PVA by abundant functional groups, achieving a robust and durable Zn anode with high reversibility. Thus, the PVA/SFs@Zn symmetric cell exhibits an ultra-long lifespan of 3150 h compared to bare Zn (182 h) at 1.0 mAh cm-2-1.0 mAh cm-2, and excellent reversibility with an average Coulombic efficiency of 99.04% under a large plating capacity for 800 cycles. Moreover, the PVA/SFs@Zn||PANI/CC full cells maintain over 20 000 cycles with over 80% capacity retention under harsh conditions at 5 and 10 A g-1. This SF-modified protective layer for Zn anode suggests a promising strategy for reliable and high-performance ZIBs.

Highly Stable Aqueous/Organic Hybrid Zinc-Ion Batteries Based on a Synergistic Cathode/Anode Interface Engineering

Zn-ion batteries (ZIBs) are developing rapidly due to their advantages of safety, moderate energy density, and abundant Zn-metal reserves. However, the dendritic growth and side reactions at the Zn-based anode and the dissolution of metallic elements at transition metal-based cathodes destabilize the electrode/electrolyte interface, which ultimately reduces the electrochemical performance of ZIBs. Herein, an aqueous/organic hybrid electrolyte that endows synergistic cathode/anode interfacial layers is proposed. On the anode, the ZnF2/Zn3(PO4)2-rich film induces the Zn nucleation, enabling a dendrite-free and corrosion-free electrode morphology. On the cathode, in contrast to Zn deposition anomalously on the cathode surface due to underpotential deposition during cycling in the unmodified electrolyte, the obtained interfacial film using the hybrid electrolyte inhibits the dissolution of metallic elements and avoids Zn deposition on the transition metal-based cathode. As a result, a pouch cell with a metallic Zn anode and a LiMn2O4 cathode (depth of discharge: 40%) based on the modified electrolyte maintains a capacity of 92 mAh g-1 after 235 cycles with a stable and clean cathode/anode interface. This research presents insight into the construction of a stable cathode/anode interface for long-cycling ZIBs.

In Situ Etching of Multifunctional Three-Dimensional Interfacial Layers for the Construction of Porous Zn Anodes with Enhanced Surface Textures

Aqueous Zn-ion batteries offer the advantages of greater security and lower fabrication costs over their lithium-ion counterparts. However, their further advancement and practical application are hindered by the drastic decay in their performance due to the uncontrollable dendrite growth on Zn anodes. In this study, we fabricated a versatile three-dimensional (3D) interfacial layer (3D PVDF-Zn(TFO)2 (PVDF: poly(vinylidene fluoride); TFO: trifluoromethanesulfonate), which simultaneously formed porous Zn-metal anodes (PZn) with an enhanced (002) texture, via a in situ etching scheme. The 3D PVDF-Zn(TFO)2@PZn symmetrical cells leverage the advantages of surface coating and 3D porous architectures to yield extra-long cyclic lifetimes of over 5300 h (0.1 mA cm-2). The fabricated anodes were found to be compatible with MnO2 cathodes, and the resulting full batteries delivered an outstanding capacity of 336 mAh g-1 at 0.1 A g-1 and exhibited impressive long-term reversibility with a capacity retention of 78.7% for 2000 cycles. The proposed coating strategy is viable for developing porous structures with cutting-edge designs and for textured surface engineering.