Unraveling the Multifunctional Mechanism of Fluoroethylene Carbonate in Enhancing High-Performance Room-Temperature Sodium-Sulfur Batteries.

Room-temperature sodium-sulfur (RT Na-S) batteries has attracted growing attentions in large-scale energy storage technology, while the serious shuttle effect and interface side reaction limit its practical application. Despite fluoroethylene carbonate (FEC) has been widely used as an electrolyte additive or co-solvent to facilitate the optimization of electrode-electrolyte interphase in RT Na-S batteries, its crucial influence and mechanism have not been clearly understood. Herein, we deeply reveal the two-steps cathode-electrolyte interphase (CEI) formation by using FEC as the exclusive electrolyte solvent.

Design towards recyclable micron-sized NaS cathode with self-refinement mechanism.

Sodium sulfide (NaS) as an initial cathode material in room-temperature sodium-sulfur batteries is conducive to get rid of the dependence on Na-metal anode. However, the micron-sized NaS that accords with the practical requirements is obstructed due to poor kinetics and severe shuttle effect. Herein, a subtle strategy is proposed via regulating NaS redeposition behaviours.

Excellent Polymerized Ionic-Liquid-Based Gel Polymer Electrolytes Enabled by Molecular Structure Design and Anion-Derived Interfacial Layer.

Polymerized ionic liquid (PIL)-based gel polymer electrolytes (GPEs) are well known as highly safe and stable electrolytes but with low ambient ionic conductivity. Herein, we first designed and synthesized an IL monomer with a long and flexible side chain and then mixed it with LiTFSI and MEMPTFSI to construct a PIL-based GPE (denoted as GM-GPE). The special molecular structure of the monomer greatly improves the ionic transport through the PIL chain, and the introduction of MEMPTFSI plasticizer further improves the ionic conductivity, promoting a TFSI-anion-derived SEI formation to suppress Li dendrite growth and forming an electrostatic shielding effect of MEMP cations to promote the uniform deposition of Li.

Co-Intercalation-Free Ether-Based Weakly Solvating Electrolytes Enable Fast-Charging and Wide-Temperature Lithium-Ion Batteries.

Ether-based electrolytes are competitive choices to meet the growing requirements for fast-charging and low-temperature lithium-ion batteries (LIBs) due to the low viscosity and low melting point of ether solvents. Unfortunately, the graphite (Gr) electrode is incompatible with commonly used ether solvents due to their irreversible co-intercalation into Gr interlayers. Here, we propose cyclopentyl methyl ether (CPME) as a co-intercalation-free ether solvent, which contains a cyclopentane group with large steric hindrance to obtain weakly solvating power with Li and a wide liquid-phase temperature range (-140 to +106 °C).