Unveiling MBenes: A New Class of 2D Materials Shaping the Future of Energy

Since the emergence of MXenes, 2D transition-metal (TM) carbides and nitrides derived from MAX phases, during the previous century, research into layered TM-based materials has significantly expanded. This focus has recently extended to 2D TM borides, identified in 2017 as potential MXene analogs and now termed MBenes. Over the last five years, MBenes have garnered increasing attention across nanotechnology, physical sciences, and chemistry, owing to their diverse and promising physicochemical properties. These materials exhibit high electrical conductivity, chemical reactivity, and mechanical robustness, suggesting substantial potential in energy storage and electrocatalysis. However, MBene research remains nascent, with many of their theoretically predicted properties yet to be experimentally confirmed. Compared to MXenes, MBenes display heightened structural complexity, including polymorphism and phase transitions, which complicates their synthesis and exfoliation into monolayer nanoflakes (NFs). This review provides a comprehensive overview of MBenes as a distinct class of 2D TM borides derived from MAB phases. Recent progress in their synthesis, characterization, and application is summarized, and ongoing challenges in both experimental fabrication and computational modeling are critically assessed. Potential directions for future research and application development are also discussed.