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

Abstract

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.