Fundamentals and design strategies of electrolytes for high-temperature zinc-ion batteries

As a promising candidate for future large-scale energy storage applications, rechargeable zinc-ion batteries (ZIBs) have experienced significant growth in the past decade due to their high capacity and reversibility of Zn metal anode, cost-effectiveness, high safety, and environmental friendliness. To promote the practical application, ZIBs should work well in both low and high-temperature environments, in which electrolyte plays a central role in achieving high performance. Although many of the challenges are common to both sets of conditions, high temperatures are more complicated for electrolyte behavior and electrode interface. Hence, it is equally important to formulate practical solutions for high-temperature (defined as 40-150 °C) applications to facilitate the commercialization of ZIBs. In this review, we first aim to shed light on the underlying causes of electrolyte failure and critical issues in high-temperature environments. Subsequently, we present a comprehensive summary and discussion of solution strategies for current different electrolytes (aqueous electrolytes, organic electrolytes, and solid-state electrolytes) and explore the possibilities of current high-temperature electrolytes from both thermodynamic and kinetic perspectives. Finally, we highlight the crucial challenges and future perspectives for high-temperature electrolytes and battery systems. The insights provided will hopefully drive the rapid development of high-temperature ZIBs, facilitating their practical applications for large-scale energy storage.