Entropy‐Driven Hydrated Eutectic Electrolytes with Diverse Solvation Configurations for All‐Temperature Zn‐ion Batteries
Meijia Qiu, Yuxuan Liang, Jiahong Hong, Jiale Li, Peng Sun, Wenjie Mai
Abstract
Abstract Batteries always encounter uncontrollable failure or performance decay under extreme temperature environments, which is largely limited by the properties of electrolytes. Herein, an entropy‐driven hydrated eutectic electrolyte (HEE) with diverse solvation configurations is proposed to expand the operating temperature range of Zn‐ion batteries. The HEE possesses over 40 types of Zn 2+ solvation structure with uniform distribution, contributing to its much higher solvation configurational entropy compared to the conventional aqueous counterpart (only 6 types). These effectively promote its anti‐freezing ability under ultralow temperatures, with a high ionic conductivity of 0.42 mS cm −1 even at a low temperature of −40 °C. Moreover, the entropy‐driven property can simultaneously enhance the thermal stability under a high temperature over +140 °C. Therefore, the HEE can enable full cells stably working over a wide temperature range of −40~+80 °C, performing over 1500 cycles with 100 % capacity retention at −40 °C and 1000 cycles with ~72 % capacity retention at +80 °C. This inspiring concept of entropy‐driven electrolyte with quantized solvation configurational entropy value has charming potential for designing future special batteries with excellent adaptability towards extreme temperature environments.