Deep Eutectic Solvents for Batteries and Fuel Cells: Biosubstitution, Advantages, Challenges, and Future Directions
Yonchen Hariyanto, Ying Ki Ng, Zhi Zhou Siew, Chu Yong Soon, Adrian C. Fisher, Leopold Kloyer, Chen Wai Wong, Eric Wei Chiang Chan
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.