Highly Hydroxide-Conductive Nanostructured Solid Electrolyte via Predesigned Ionic Nanoaggregates

Recent Advances and Challenges in Anion Exchange Membranes Development/Application for Water Electrolysis: A Review

In recent years, anion exchange membranes (AEMs) have aroused widespread interest in hydrogen production via water electrolysis using renewable energy sources. The two current commercial low-temperature water electrolysis technologies used are alkaline water electrolysis (AWE) and proton exchange membrane (PEM) water electrolysis. The AWE technology exhibited the advantages of high stability and increased cost-effectiveness with low hydrogen production efficiency. In contrast, PEM water electrolysis exhibited high hydrogen efficiency with low stability and cost-effectiveness, respectively. Unfortunately, the major challenges that AEMs, as well as the corresponding ion transportation membranes, including alkaline hydrogen separator and proton exchange membranes, still face are hydrogen production efficiency, long-term stability, and cost-effectiveness under working conditions, which exhibited critical issues that need to be addressed as a top priority. This review comprehensively presented research progress on AEMs in recent years, providing a thorough understanding of academic studies and industrial applications. It focused on analyzing the chemical structure of polymers and the performance of AEMs and established the relationship between the structure and efficiency of the membranes. This review aimed to identify approaches for improving AEM ion conductivity and alkaline stability. Additionally, future research directions for the commercialization of anion exchange membranes were discussed based on the analysis and assessment of the current applications of AEMs in patents.

Hierarchically Nanostructured Solid-State Electrolyte for Flexible Rechargeable Zinc-Air Batteries

The construction of safe and environmentally-benign solid-state electrolytes (SSEs) with intrinsic hydroxide ion-conduction for flexible zinc-air batteries is highly desirable yet extremely challenging. Herein, hierarchically nanostructured CCNF-PDIL SSEs with reinforced concrete architecture are constructed by nanoconfined polymerization of dual-cation ionic liquid (PDIL, concrete) within a robust three-dimensional porous cationic cellulose nanofiber matrix (CCNF, reinforcing steel), where plenty of penetrating ion-conductive channels are formed and undergo dynamic self-rearrangement under different hydrated levels. The CCNF-PDIL SSEs synchronously exhibit good flexibility, mechanical robustness, superhigh ion conductivity of 286.5 mS cm^-1 , and decent water uptake. The resultant flexible solid-state zinc-air batteries deliver a high-power density of 135 mW cm^-2 , a specific capacity of 775 mAh g^-1 and an ultralong cycling stability with continuous operation of 240 hours for 720 cycles, far outperforming those of the state-of-the-art solid-state batteries. The marriage of biomaterials with the diversity of ionic liquids creates enormous opportunities to construct advanced SSEs for solid-state batteries.

High-Charge Density Polymerized Ionic Networks Boosting High Ionic Conductivity as Quasi-Solid Electrolytes for High-Voltage Batteries

Solid-state electrolytes are actively sought for their potential application in energy storage devices, especially lithium metal rechargeable batteries. However, one of the key challenges in the development of solid-state electrolytes is their lower ionic conductivity compared with that of liquid electrolytes (10^-2 S cm^-1 at room temperature), where a large gap still exists. Therefore, the pursuit of high ionic conductivity equal to that of liquid electrolytes remains the main objective for the design of solid-state electrolytes. Here, we show a series of high-charge density polymerized ionic networks as solid-state electrolytes that take inspiration from poly(ionic liquid)s. The obtained quasi-solid electrolyte slice displays an astonishingly high ionic conductivity of 5.89 × 10^-3 S cm^-1 at 25 °C (the highest conductivity among those of the state-of-art polymer gel electrolytes and polymer solid electrolytes) and ultrahigh decomposition potential, >5.2 V versus Li/Li⁺, which are attributed to the continuous ion transport channel formed by an ultrahigh ion density and an enhanced chemical stability endowed by highly cross-linked networks. The Li/LiFePO₄ and Li/LiCoO₂ batteries (3.0-4.4 V) assembled with the solid electrolytes show high stable capacities of around 155 and 130 mAh g^-1, respectively. In principle, our work breaks new ground for the design and fabrication of the solid-state electrolytes in various energy conversion devices.