Synergistic Design of MXene Architectures for Mechanically Robust and High-Performance Flexible Batteries and Supercapacitors

The rapid advancement in wearable, portable, and foldable electronic devices has underscored inherent deficiencies in conventional energy storage technologies, particularly with respect to mechanical compliance and device miniaturization. Overcoming these limitations demands energy storage solutions that integrate high electrochemical performance with mechanical resilience and scalability. In this context, MXenes, two-dimensional (2D) transition metal carbides, nitrides, or carbonitrides, have emerged as promising candidates due to their outstanding electrical conductivity, tunable surface chemistry, and intrinsic flexibility. Unlike previous reviews that focus primarily on MXene synthesis or individual device performance, this work provides a synergistic and cross-disciplinary perspective on the structural design of MXene architectures for flexible energy storage systems. It critically correlates hierarchical structural engineering (such as composite integration, dimensional hybridization, and interface modulation) with the mechanical and electrochemical behaviors of MXenes in various device configurations, including flexible batteries and supercapacitors (SCs). Particular attention is given to mechanical-electrochemical coupling mechanisms that govern flexibility retention, strain accommodation, and charge transport dynamics. Furthermore, this review offers a comparative discussion across multiple chemistries, encompassing Li-, Na-, Zn-, and K-ion batteries and SCs, thereby providing an integrative understanding of MXene functionality beyond single-system studies. Finally, this review outlines emerging design principles, fabrication strategies, and research directions aimed at achieving scalable, durable, and high-performance MXene-based flexible energy storage technologies. This synergistic perspective bridges the gap between mechanical engineering and electrochemical optimization, offering new insights for the next generation of flexible and wearable power systems.