Dual-functional surface of MXene anodes boosts long-term cyclability of lithium-metal batteries

Abstract

Introducing seed elements with high lithiophilicity onto the anode is a promising strategy to mitigate dendrite growth in lithium metal batteries (LMBs). Two primary seed elements have been explored: (i) lithiophilic metals (e.g. Ag, Au, and Sn), and (ii) fluorine (–F) functionalities. Despite significant advancements, hybrid materials combining the two elements have not been realized. Moreover, it remains unclear which element enhances LMB performance more. In this study, we engineered, for the first time, a high-density dual-functional surface incorporating lithiophilic metals and –F functionalities. Through rapid Joule heating, we integrated high-density Au nanoparticles (Au NPs) onto the F-terminated Ti₃C₂T_x MXene anode surface. Our findings reveal distinct roles for each element: Au NPs reduce the size of deposited lithium, while –F functionalities promote uniform lithium distribution with a LiF-rich solid electrolyte interphase (SEI) layer. Notably, the synergistic effect of Au NPs and –F functionalities extended the lifespan of Au@F-rich Ti₃C₂T_x to 600 cycles compared to the initial 100 cycles of Ti₃C₂T_x and 240 cycles of Au@Ti₃C₂T_x. These results underscore the pivotal role of –F functionalities in prolonging and enhancing the performance of LMBs. This research highlights the importance of tailored surface functionalities and offers a promising pathway for the design of advanced LMB components.