Synergistically Inducing Ultrafast Ion Diffusion and Reversible Charge Transfer in Lithium Metal Batteries Using Bimetallic Molybdenum-Titanium MXenes

Metal batteries have captured significant attention for high-energy applications, owing to their superior theoretical energy densities. However, their practical viability is impeded by severe dendrite formation and poor cycling stability. To alleviate these issues, a 3D-structured bimetallic-Mo₂Ti₂C₃T_x based fiber electrode was fabricated in this study and analyzed experimentally and computationally. The bimetallic Mo-Ti composition of MXenes synergistically achieved low binding and formation energies with lithium. In particular, the minimal lattice mismatch between the deposited Li metal and the Mo₂Ti₂C₃T_x MXene anode substrate led to improved Li formation energy with respect to the MXene surface. Moreover, the synergy of the bimetallic Mo-Ti composition of the Mo₂Ti₂C₃T_x MXene fiber substrate helped to amplify ion diffusion and reversible charge transfer. Consequently, the bimetallic MXene electrode exhibited an impressive Coulombic efficiency (99.08%) even at a high current density (5 mA cm^-2) and a fixed cutoff capacity of 1 mA h cm^-2 with prolonged cycle life (650 cycles). This report highlights a promising advancement in addressing the critical challenges facing metal battery operation, thereby offering an approach to improving performance for high-energy applications.