Currently, the practical application of liquid lithium-ion batteries faces challenges in meeting the requirements of high energy density and safety. To address concerns such as electrolyte leakage and flammability, solid polymer electrolytes (SPEs) have emerged as promising alternatives to liquid electrolytes. SPEs, particularly those synthesized via in situ polymerization processes, offer advantages in establishing robust interface contacts and compatibility with existing industrial production lines. However, the electrochemical stability of SPEs remains a hurdle for high-voltage lithium metal batteries (LMBs). To enhance interface uniformity, electrochemical stability, and thermal stability, researchers commonly employ fluorination strategies, thus expanding the potential of SPEs in high-voltage, long-cycling LMBs. Fluorine plays a crucial role in achieving these objectives due to its high electronegativity, polarization, outstanding dielectric properties, strong bond strength, stability, and hydrophobic nature. In this study, we delve into how fluorinated electrolytes improve interface stability between SPEs and electrodes by examining their underlying mechanisms. Besides, we provide an overview of current fluorination strategies and their impact on battery performance. Furthermore, we discuss challenges and issues associated with current in situ polymerized fluorinated SPE routes and propose practical strategies for consideration.

Iron-based aqueous redox flow batteries (IBA-RFBs) represent a promising solution for long-duration energy storage, supporting the integration of intermittent renewable energy into the grid, thanks to their commendable safety profile and cost-effectiveness. Membranes, serving as pivotal components in redox flow batteries (RFBs), play a crucial role in facilitating ion conduction for internal circuit formation while preventing the crossover of redox-active species. Given their direct impact on RFB performance and cost, membranes merit considerable attention. This review provides an overview of recent advancements in membranes tailored for IBA-RFBs. Initially, it delineates the operational mechanisms of various IBA-RFB configurations. Subsequently, it delves into key performance metrics for evaluating membrane efficacy, dissecting the intricate interplay between membrane performance and overall IBA-RFB efficiency. Building upon this foundation, the review spotlights recent breakthroughs in ion exchange membranes and porous membranes designed specifically for IBA-RFBs, showcasing their remarkable ability to bolster battery efficiency, cycling stability, and cost-effectiveness. Lastly, this review outlines future directions for membrane development, offering some insights to propel the widespread adoption of IBA-RFBs on a large scale.

Aqueous zinc ion batteries (AZIBs), renowned for their high theoretical energy density, safety, cost-effectiveness and eco-friendliness, offer immense potential in the realm of energy storage and conversion, finding applications in renewable energy and portable devices. However, the development of AZIBs still faces several challenges related to the electrochemical behavior of zinc anodes in aqueous electrolytes, primarily zinc dendrite formation, which emphasize the critical need for a fundamental understanding of the interfacial phenomena between the electrode and electrolyte. This review focuses on the three models: the electric double layer (EDL) model, the solvation structure model, and the Zn/electrolyte interface model. They guide the design of the electrolyte system in AZIBs. These models provide a comprehensive understanding of the interactions between the electrode, electrolyte, and the solvated ions in the system. By optimizing the salt types, salt concentrations, solvents and additives based on these models, it is possible to enhance the performance of AZIBs, including their energy density, cycle life, and safety. The review also highlights recent research progress in electrolyte modification of AZIBs for understanding battery behavior, along with perspectives for the direction of further investigations.

Researchers prefer mild aqueous static zinc-ion batteries (ASZIBs) for their distinct benefits of excellent safety, abundant zinc resources, low cost, and high energy density. However, at the moment there are some issues with the cathode materials of mild ASZIBs, including dissolution, by-products, poor conductivity, and a contentious energy storage system. Consequently, there are numerous difficulties in the development of high-performance mild ASZIBs cathode materials. This overview examines the mechanisms for storing energy and the developments in inorganic, organic, and other novel cathode materials that have emerged in recent years. At the same time, three solutions—structural engineering, interface engineering, and reaction pathway engineering—as well as the difficulties now faced by the cathode materials of mild ASZIBs are forcefully introduced. Finally, a prospect is made regarding the evolution of cathode materials in the future.

Electricity-driven water splitting to convert water into hydrogen (H₂) has been widely regarded as an efficient approach for H₂ production. Nevertheless, the energy conversion efficiency of it is greatly limited due to the disadvantage of the sluggish kinetic of oxidation evolution reaction (OER). To effectively address the issue, a novel concept of hybrid water electrolysis has been developed for energy–saving H₂ production. This strategy aims to replace the sluggish kinetics of OER by utilizing thermodynamically favorable organics oxidation reaction to replace OER. Herein, recent advances in such water splitting system for boosting H₂ evolution under low cell voltage are systematically summarized. Some notable progress of different organics oxidation reactions coupled with hydrogen evolution reaction (HER) are discussed in detail. To facilitate the development of hybrid water electrolysis, the major challenges and perspectives are also proposed.

Sulfide solid electrolyte (SE) is one of the most promising technologies for all-solid-state batteries (ASSBs) because of its high ionic conductivity and ductile mechanical properties. In order to further improve the energy density of sulfide-based ASSBs and promote practical applications, silicon anodes with ultrahigh theoretical capacity (4,200 mAh·g⁻¹) and rich resource abundance have broad commercial prospects. However, significant challenges including bulk instability of sulfide SEs and poor utilization of silicon materials have severely impeded the ASSBs from becoming viable. In this review, we first introduce the critical bulk properties of sulfide SEs and the most recent improving strategies covering the ionic conductivity, air stability, electrochemical window, mechanical stability, thermostability and solvent stability. Next, we introduce the main factors affecting the compatibility of silicon and sulfide SE, including the carbon’s effect, particle size of silicon, external pressure, silicon composite matrix and the depth of silicon’s lithiation. Finally, we discuss possible research directions in the future. We hope that this review can provide a comprehensive picture of the role of nanoscale approaches in recent advances in ASSBs with sulfide and silicon, as well as a source of inspiration for future research.