Deep Eutectic Solvents for Batteries and Fuel Cells: Biosubstitution, Advantages, Challenges, and Future Directions

Abstract

The rapid shift toward electric vehicles (EVs) is imperative for achieving the United Nations’ net-zero emissions target by 2050. This paper explores deep eutectic solvents (DESs) as sustainable alternatives to traditional solvents in batteries and fuel cells. DESs, sourced from renewables, offer numerous advantages, including low toxicity, affordability, and biodegradability, aligning with sustainable energy goals. The review underscores the importance of addressing challenges such as high viscosity, limited solubility, and compatibility issues for enhanced performance. This study primarily delves into how DESs can boost electrolyte performance through biosubstitution and ion recovery, extending their potential to metal recovery for resource efficiency. Additionally, DESs’ flame-retardant, antifreeze properties, and robust thermal and electrochemical stability enhance battery safety, positioning them as a promising avenue for future research. Given the ambitious EV transition targets set globally, this Review provides an overview of DES advancements and their integration with other materials and technologies. Despite potential drawbacks in specific energy and energy density, sodium-based batteries are emerging as a viable alternative to their lithium counterparts. The future of EVs and DESs in battery technology hinges on their economic viability, infrastructure development, and life cycle emissions. In conclusion, this study underscores the pivotal role of DESs in driving sustainable energy solutions during the EV transition.

Thermostable Deep Eutectic Solvents for Thermochemical Reactions: Novel Stability Indicators

“…Additionally, the alkyl side chains in the choline compound could also influence the thermostability of the DES. , Longer alkyl chains could potentially lead to a decrease in the stability of the DES, resulting in a higher rate of decomposition at elevated temperatures . Furthermore, the presence of water in the DES can also affect its thermostability . Water can act as a plasticizer in the DES, reducing its viscosity and improving its fluidity .…”

“…Type III DES is a completely organic system, with a quaternary ammonium salt as the HBA mixed with other organic molecules like glycerol and lactic acid as HBD. Type IV DES, on the other hand, is an organometallic solvent with the metal chloride hydrate acting as the HBA. , …”

“…Additionally, the tunability of DESs can be achieved by altering the structure or ratio of their components . With attributes such as low toxicity, flammability, and vapor pressure, DESs are increasingly favored across various applications, including chemical reactions, batteries, supercapacitors, and biofuel production. , …”

“…Consequently, thermostable DESs emerge as a promising alternative, promising not only to improve process efficiency and yield, but also to significantly reduce energy consumption . Moreover, their low vapor pressure enhances safety by facilitating operations at ambient pressure, thereby mitigating risks associated with fume release or explosions, making them a safer, more sustainable choice in the field of green chemistry …”

Review on Oxygen Release Mechanism and Modification Strategy of Nickel-Rich NCM Cathode Materials for Lithium-Ion Batteries: Recent Advances and Future Directions

“…However, addition of excess S additives increases the CEI film thickness, hinders Li + diffusion, increases the interfacial resistance, resulting in the reduction of the electrochemical performance, so improving the composition of the electrolyte system components could be considered to be effective to enhance the battery performance. Deep eutectic solvents (DESs) with flame retardant and antifreeze properties as well as strong thermal and electrochemical stability improve the safety of batteries and have the advantages of low toxicity, affordability, and biodegradability, which make DESs a promising research area for future studies . The application of new ether-based electrolyte can also improve battery performance.…”