Thermal Warning and Shut-down of Lithium Metal Batteries Based on Thermoresponsive Electrolytes

The thermal runaway issue represents a long-standing obstacle that retards large-scale applications of lithium metal batteries. Various approaches to inhibit thermal runaway suffer from some intrinsic drawbacks, either being irreversible or delayed thermal protection. Herein, this work has explored thermo-responsive lower critical solution temperature (LCST) ionic liquid-based electrolytes, which provides reversible overheating protection for batteries with warning and shut-down stages, well corresponding to an initial stage of thermal runaway process. The batteries could function stably below 70 °C as a working mode, while demonstrating a warning mode above 80 °C with a noticeable reduction in specific capacitance to delay temperature increase of batteries. In terms of 110 °C as a critically dangerous temperature, a shut-down mode is designed to minimize the thermal energy releasing as the batteries are barely chargeable and dischargeable. Dynamically growing polymeric particles above LCST contributed to such an intelligent and mild control on specific capacitance. Larger size will occupy larger surfaces of electrodes and close more pores of separators, enabling a gradual suppressing of Li+ transfer and reactions. The present work demonstrated a scientific design of thermoresponsive LCST electrolytes with a superiorly precise and intelligent control of electrochemical performances to achieve self-adapted overheating protections.

Electro-casting for Superior Gas Separation Membrane Performance and Manufacturing

Gas separation polymer membranes play a pivotal role in various industrial processes including carbon capture and hydrogen production. However, the inherent trade-off between permeability and selectivity coupled with challenges in membrane manufacturing has hindered their widespread industrial deployment. To address the permselectivity challenges, researchers have explored increasingly complex polymers, composite systems, and other materials. In this study, we introduce a novel membrane manufacturing technique called "electro-casting" that not only enables efficient membrane fabrication but also enhances the trade-off of traditional polymer-based membranes. We fabricated cellulose acetate (CA) membranes embedded with 1-ethyl-3-methyl imidazolium via electro-casting and performed a comparative analysis of structural, morphological, and gas transport characteristics against membranes made via conventional casting techniques. We discovered that electro-casted membranes exhibited a unique crystalline structure, surface topology that induced a remarkable 200% improvement in CO2/N2 selectivity and a 110% increase in CO2/CH4 selectivity. The electric field generated during the manufacturing process played a crucial role in altering the supramolecular structure of the polymer, thereby increasing the separation properties of the membranes as well as their thermal and mechanical features. Electro-casting induced a polymer crystallization effect that disrupted the permeability-selectivity trade-off observed in conventional membranes, while producing highly stable membranes. Moreover, the simplicity of this manufacturing method and its significant impact on membrane properties have the potential to accelerate the deployment of gas separation membranes, facilitating the transition toward a NetZero chemical industry.

Adaptive Ion-Gel: Stimuli-Responsive, and Self-Healing Ion Gels

Ion gels are an emerging class of polymer gels in which a three-dimensional polymer network swells with an ionic liquid. Ion gels have drawn considerable attention in various fields such as energy and biotechnology owing to their excellent properties including nonvolatility, nonflammability, high ionic conductivity, and high thermal and electrochemical stability. Since the first report on ion gels (published ∼30 years ago), diverse functional ion gels exhibiting impressive physicochemical properties have been reported. In this review, recent developments in functional ion gels that can modulate their physical properties in response to environmental conditions are outlined. Stimuli-responsive ion gels that can adaptively undergo phase transitions in response to thermal and light stimuli are initially discussed, followed by an evaluation of diverse self-healing ion gels that can spontaneously mend mechanical damage through judiciously designed ion-gel networks.