Hydrogel Electrolyte Enabled High-Performance Flexible Aqueous Zinc Ion Energy Storage Systems toward Wearable Electronics

Gyroid Liquid Crystals as Quasi-Solid-State Electrolytes Toward Ultrastable Zinc Batteries

The potential for optimizing ion transport through triply periodic minimal surface (TPMS) structures renders promising electrochemical applications. In this study, as a proof-of-concept, we extend the inherent efficiency and mathematical beauty of TPMS structures to fabricate liquid-crystalline electrolytes with high ionic conductivity and superior structural stability for aqueous rechargeable zinc-ion batteries. The specific topological configuration of the liquid-crystalline electrolytes, featuring a Gyroid geometry, enables the formation of a continuous ion conduction pathway enriched with confined water. This, in turn, promotes the smooth transport of charge carriers and contributes to high ionic conductivity. Meanwhile, the quasi-solid hydrophobic phase assembled by hydrophobic alkyl chains exhibits notable rigidity and toughness, enabling uniform and compact dendrite-free Zn deposition. These merits synergistically enhance the overall performance of the corresponding full batteries. This work highlights the distinctive role of TPMS structures in developing high-performance, liquid-crystalline electrolytes, which can provide a viable route for the rational design of next-generation quasi-solid-state electrolytes.

A Hydrogel Electrolyte with High Adaptability over a Wide Temperature Range and Mechanical Stress for Long-Life Flexible Zinc-Ion Batteries

Flexible zinc-ion batteries have garnered significant attention in the realm of wearable technology. However, the instability of hydrogel electrolytes in a wide-temperature range and uncontrollable side reactions of the Zn electrode have become the main problems for practical applications. Herein, N,N-dimethylformamide (DMF) to design a binary solvent (H2 O-DMF) is introduced and combined it with polyacrylamide (PAM) and ZnSO4 to synthesize a hydrogel electrolyte (denoted as PZD). The synergistic effect of DMF and PAM not only guides Zn2+ deposition on Zn(002) crystal plane and isolates H2 O from the Zn anode, but also breaks the hydrogen bonding network between water to improve the wide-temperature range stability of hydrogel electrolytes. Consequently, the symmetric cell utilizing PZD can stably cycle over 5600 h at 0.5 mA cm- 2 @0.5 mAh cm-2 . Furthermore, the Zn//PZD//MnO2 full cell exhibits favorable wide-temperature range adaptability (for 16000 cycles at 3 A g-1 under 25 °C, 750 cycles with 98 mAh g-1 at 0.1 A g-1 under -20 °C) and outstanding mechanical properties (for lighting up the LEDs under conditions of pressure, bending, cutting, and puncture). This work proposes a useful modification for designing a high-performance hydrogel electrolyte, which provides a reference for investigating the practical flexible aqueous batteries.

Recent Advances on Stretchable Aqueous Zinc-Ion Batteries for Wearable Electronics

The rapid development of wearable electronics has stimulated the pursuit of advanced stretchable power sources. As a promising candidate, stretchable aqueous zinc-ion batteries (AZIBs), have attracted unprecedented attention owing to their intrinsic safety, low cost, environmental benignity, and high performance, and can be endowed with additional functionalities to broaden the applications of wearable electronics. Here, a comprehensive review on the latest advances of stretchable AZIBs is presented. The materials and methods for stretchable components in AZIBs are first summarized, covering current collectors, electrodes, electrolytes/separators, and encapsulating layers. Subsequently, the benefits of the coplanar, fiber-shaped, and sandwiched configurations for stretchable AZIBs are analyzed. Moreover, the additional features integrated into stretchable AZIBs are highlighted. Finally, the challenges and prospects of stretchable AZIBs for wearable applications in the future are proposed.