Synthesis of d-Ti3N MXene for potassium ion symmetric coin cell super capacitors

Abstract

Nitride-based MXenes offer advantages over their carbide and carbonitride counterparts, such as stronger M−X bond resulting in higher stability, making them particularly promising energy storage material. However, current inventory of nitride based MXenes is limited to only few materials such as Ti₄N₃, Ti₃N₂ and Ti₂N. In this study delaminated Ti₃N, a novel 2d MXene, was fabricated by selective etching of Aluminum from Ti₃AlN using molten salt and hydrofluoric (HF) acid, expanding the family of MXene materials and opening new avenues for energy storage applications. Material was characterized to confirm the crystal structure, morphology, elemental composition and oxidation states using various techniques. Moreover, the electrochemical results demonstrate that d-Ti₃N MXene synthesized from mixture of molten salt has high specific capacitance of 76 Fg⁻¹, which is 36 Fg⁻¹ for HF acid synthesis. Additionally, after 5000 cycles, the d-Ti3N MXene retains 87 % of its original capacity, demonstrating good cyclic stability. Furthermore, with 610 W kg⁻¹ power density, a symmetric capacitor based on d-Ti3N MXene can provide 4.4 Wh kg⁻¹ energy density. This demonstrates the potential of newly synthesized material in pseudocapacitors and other energy storage.