Borophene in energy storage technologies: Structural insights, functional performance, and future directions

Borophene, a novel two-dimensional (2D) allotrope of boron, has rapidly emerged as a promising material for next-generation energy storage technologies owing to its exceptional physicochemical, mechanical, electronic, and thermal properties. This review provides a comprehensive outline of current advances in the synthesis, structural characteristics, and functional capabilities of borophene and its derivatives. Key synthesis routes, including both top-down and bottom-up approaches, are discussed in the context of material quality, scalability, and substrate interactions. The unique polymorphic nature and anisotropic behavior of borophene are examined through a structural understanding, supported by density functional theory and experimental findings. Particular attention is given to the application of borophene in energy storage systems such as lithium-ion and sodium-ion batteries, supercapacitors, and hydrogen storage devices. Functional enhancements through heterostructure formation, elemental doping, and surface modifications are critically analyzed. The paper concludes with a discussion on the challenges and future directions for leveraging full potential of borophene in sustainable and high-performance energy storage applications.