Nb-based MXenes : Structures, properties, synthesis, and application towards supercapacitors

Energy storage materials have gained significant attention over the past two decades. MXenes, an excellent two-dimensional (2D) material is the most recent and active member of the 2D family which is studied extensively. Among various MXenes, Ti-MXene has emerged as a widely utilized material. However, other transition metal alternatives also potentially serve the function of 2D MXene for various applications. Hence, non-Ti-based MXenes, particularly niobium (Nb) based MXenes (Nb₂CT_x and Nb₄C₃T_x) have recently gained interest due to their unique properties. This article reviews the structures, properties, various synthesis routes, and applications of Nb-based MXenes, specifically focusing on their utilization in supercapacitors. The paper discusses the recent findings and concludes by addressing the future prospects of Nb-based MXenes for supercapacitor applications. © 2024 Elsevier Ltd.