A comprehensive review of double transition metal MXene (Mo₂Ti₂C₃T_x) in energy storage, conversion, and harvesting

Molybdenum titanium carbide (Mo₂Ti₂C₃T_x), an emerging double-transition-metal (DTM) carbide MXene, has attracted considerable interest due to its exceptional physicochemical properties and diverse applications in energy-related technologies. This review provides a comprehensive overview of recent progress in Mo₂Ti₂C₃T_x research, focusing on synthesis strategies, structural characteristics, and energy storage and conversion capabilities. The key aspects discussed include the intrinsic structural and electrochemical properties of the material, which contribute to its outstanding performance in supercapacitors, lithium-ion batteries, and electrocatalytic applications. Their high electrical conductivity, large surface area, and chemical stability underlie their efficiency in these applications. In addition, its thermoelectric potential, which is highlighted by its high Seebeck coefficient and power factor, makes it a promising energy-harvesting material. Despite these advantages, challenges remain in achieving scalable production, long-term operational stability, and comprehensive mechanistic understanding of interfacial processes and degradation pathways. Future research should prioritise hybrid architectures combining Mo₂Ti₂C₃T_x with polymers, 2D materials, or metal oxides to intensify synergistic effects, as well as computational modelling to unravel the structure-property relationships. Addressing scalability through eco-friendly, high-yield synthesis routes is pivotal for the transition of laboratory-scale innovations into commercial applications. By summarising recent advancements and identifying critical research gaps, this review aims to facilitate further development and practical use of Mo₂Ti₂C₃T_x MXene in next-generation energy technologies.