Boosting Li-CO₂ Battery Performance via High-Entropy Alloy Catalysts: Insights into Configurational Entropy Effect

Li-CO₂ batteries have attracted considerable attention for their ability to combine CO₂ fixation and conversion with high-density energy storage. However, sluggish kinetics of CO₂ 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-CO₂ 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-CO₂ 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-CO₂ batteries. This work provides insights into high-entropy engineering for advanced electrocatalysts in Li-CO₂ batteries.