Boosting Li−CO 2 Battery Performance via High‐Entropy Alloy Catalysts: Insights into Configurational Entropy Effect

Abstract Li−CO 2 batteries have attracted considerable attention for their ability to combine CO 2 fixation and conversion with high‐density energy storage. However, sluggish kinetics of CO 2 reduction and evolution reactions at cathodes lead to large overpotentials and poor cyclic stability. To address this issue, it is critical to develop advanced cathode catalysts. High‐entropy alloys (HEAs), a new class of catalysts, have exhibited exceptional catalytic activities in various electrochemical reactions. Nevertheless, the intrinsic relationship between mix configurational entropy (▵S mix ) and catalytic properties of HEAs remains unclear. Herein, we prepared a series of quinary FeCoNiCuRu alloys with different ▵S mix values supported on carbon nanofibers as cathode catalysts in Li−CO 2 batteries. Experimental and computational results reveal a positive correlation between ▵S mix and catalytic activity, attributed to charge redistribution among elements with different electronegativities. The Li−CO 2 battery using the alloy catalyst with the maximum ▵S mix value delivers the largest capacity of 6160 mAh g −1 , the lowest charge potential plateau below 4.0 V, and remarkable cycling stability (550 cycles/5500 h), surpassing most reported Ru‐based catalysts. Furthermore, fabrication of pouch cells with low noble metal loading demonstrates the practical potential of HEAs for Li−CO 2 batteries. This work provides insights into high‐entropy engineering for advanced electrocatalysts in Li−CO 2 batteries.