Carbon modified MXene through gas thermal penetration treatment for electrochemical energy storage

MXenes are highly promising materials for diverse applications due to their adjustable surface chemistry and metallic conductivity. However, high-temperature processing often exacerbates MXene oxidation even at inert atmosphere, leading to a substantial reduction in electrical conductivity. Despite this, high-temperature treatment can introduce beneficial features such as increased –O active sites and decreased interflake resistance. In this study, we introduce a novel gas-thermal penetration method using formamide to deposit a uniform carbon layer on Ti₃C₂T_x MXene. This approach enhances electron transport between the carbon layer and Ti₃C₂T_x, effectively addressing the challenge of slow electron transmission associated with high-temperature treated Ti₃C₂T_x. DFT calculations reveal evident charge transfer from the deposited carbon layer to the Ti₃C₂T_x nanosheet, driven by interfacial electronic interactions, which enhances the conductivity and electrochemical properties of the hybrid material. The resultant 500-Ti₃C₂T_x demonstrates a significant increase in specific capacitance (121 F/g), a 2.9-fold improvement over pristine Ti₃C₂T_x, due to the enhanced –O terminations, faster electron transport and expanded interlayer spacing. Additionally, 500-Ti₃C₂T_x exhibits improved cycling stability with 97.6 % capacity retention after 5000 cycles at 10 A/g. This method offers a scalable and industrially viable strategy to simultaneously enhance the electrical conductivity and charge storage capabilities of MXenes.