Ti2TaC2: A novel out-of-plane ordered MXene towards flexible and cytocompatible supercapacitors

Abstract

Exploring biocompatible and flexible supercapacitor electrode material is crucial for expanding the development of health monitoring bioelectronics. MXene films, due to their low cost, high conductivity, and excellent durability under different deformation conditions, are highly competitive in bioelectronic device applications compared with traditional carbon-based materials. Herein, a novel out-of-plane ordered double transition metal MXene (Ti2TaC2) is elaborately designed and originally synthesized, where Ti atoms preferentially reside in the outer transition metal layer and Ta atoms occupy in the middle layer. Theoretical calculations prove that the introduction of Ta species into Ti3C2 MXene enlarges the work function, raises the d-band center close to Fermi level and increases the density of states of d-orbital. Consequently, the Ti2TaC2 film delivers high specific capacitance of 313 F g(-1) at 2 mV s(-1) and excellent cycling stability without capacitance loss after 10,000 cycles at 10 A/g. Furthermore, the safety and cytotoxicity of Ti2TaC2 material are innovatively evaluated in vitro multiple cell lines (e.g., 293T, bEnd.3, PC-12, BV2 and HUVEC cells) and implanted into the subcutaneous tissue of mice, proving its good biosafety and cytocompatibility. The results suggest that flexible Ti2TaC2 MXene film may be a promising cytocompatible electrode material for long-term health monitoring bioelectronics.