Additive manufacturing of MXene electrodes: from rheology-tunable nanoinks to size-scalable integrated electronics

Additive manufacturing (AM) has emerged as a transformative strategy for translating nanoscale materials into wafer-scale functional architectures, empowering the scalable fabrication of advanced electronics and energy systems. MXenes-a class of two-dimensional transition metal carbides and nitrides-exhibit exceptional electrical conductivity, tunable surface terminations, and mechanical compliance, positioning them as ideal candidates for AM-driven printed electronics. This review uniquely emphasizes the rheological-structural-functional correlations that underpin the evolution of MXene inks from individual nanosheets to architected wafer-scale systems. We dissect critical rheological parameters-including shear-thinning behavior, yield stress, and colloidal stability-and their decisive roles in shaping printability, pattern resolution, and post-print structural fidelity across AM techniques such as direct ink writing, spray coating, and electrohydrodynamic printing. Furthermore, the multiscale influence of rheology on printed micro-/nanostructures and their downstream impacts on electronic, electrochemical, and sensing performance are systematically analyzed. We summarize the latest advances in scalable MXene integration for applications including microsupercapacitors, field effect transistors (FETs), and self-powered biosensors. Finally, we highlight future research directions encompassing machine-learning-assisted ink formulation, hierarchical porous structure design, and eco-conscious processing paradigms. These insights pave the way for intelligent ink systems and hybrid device architectures, propelling MXene electronics toward multifunctional, sustainable, and industry-compatible futures.