Dendrite-free aluminum metal anode enabled by work function engineering

The uncontrolled deposition behavior, sluggish reaction kinetics and inefficient utilization of Al derived from unstable anode/electrolyte interface have severely impeded the development of aluminum-ion batteries. Here, we discuss the impact of interfacial electron/ion transfer on the electrochemical performance, and as an illustration, propose the construction of Cu@MXene as anodic current collector through work function engineering to simultaneously achieve homogeneous deposition morphology and rapid plating/stripping rate. The difference in work function between Cu nanoparticles and Ti₃C₂ MXene facilitates charge redistribution in the anode/electrolyte interface and enhances the electron availability, optimizing the interfacial electron/ion transfer behavior. This, in turn, endows Cu@MXene with elevated catalytic efficiency for desolvation reactions and robust reduction ability for the Al plating process. As a result, Cu@MXene enables a high coulombic efficiency of 99.87 % even at a high current density of 10 mA cm⁻², and sustains reversible Al plating/stripping cycles for over 3200 h at a typical current density of 1 mA cm⁻². Notably, by coupling graphite cathode and Cu@MXene-Al anode under a limited N/P ratio of 2.2, the full cell exhibits durable lifetime for 2000 cycles with an impressive energy density of 119.6 Wh kg⁻¹ (based on the total mass of cathode and anode). This work highlights a fundamental understanding of interfacial interactions in the Al deposition process and offer sustainability motivations in designing highly reversible anodes for high-energy-density aluminum-ion batteries.