Thermally Conductive Ti3C2Tx Fibers with Superior Electrical Conductivity

Abstract

High-performance Ti3C2Tx fibers have garnered significant potential for smart fibers enabled fabrics. Nonetheless, a major challenge hindering their widespread use is the lack of strong interlayer interactions between Ti3C2Tx nanosheets within fibers, which restricts their properties. Herein, a versatile strategy is proposed to construct wet-spun Ti3C2Tx fibers, in which trace amounts of borate form strong interlayer crosslinking between Ti3C2Tx nanosheets to significantly enhance interactions as supported by density functional theory calculations, thereby reducing interlayer spacing, diminishing microscopic voids and promoting orientation of the nanosheets. The resultant Ti3C2Tx fibers exhibit exceptional electrical conductivity of 7781 S cm−1 and mechanical properties, including tensile strength of 188.72 MPa and Young’s modulus of 52.42 GPa. Notably, employing equilibrium molecular dynamics simulations, finite element analysis, and cross-wire geometry method, it is revealed that such crosslinking also effectively lowers interfacial thermal resistance and ultimately elevates thermal conductivity of Ti3C2Tx fibers to 13 W m−1 K−1, marking the first systematic study on thermal conductivity of Ti3C2Tx fibers. The simple and efficient interlayer crosslinking enhancement strategy not only enables the construction of thermal conductivity Ti3C2Tx fibers with high electrical conductivity for smart textiles, but also offers a scalable approach for assembling other nanomaterials into multifunctional fibers.

1. Introduction

The rapid development of wearable devices, flexible electronics, and aerospace has highlighted the growing challenges of signal delay and overheating in high-performance electronics, making it difficult for existing fibers to meet the dual needs of fast signal transmission and efficient heat dissipation [1, 2]. Consequently, novel fibers are urgently needed to seamlessly integrate high electrical and thermal conductivity to enhance the signal transmission efficiency and stability of advanced electronics [3–5]. Ti3C2Tx, as a novel two-dimensional nanomaterial, has emerged as an ideal candidate for producing high-performance fibers due to its exceptional electrical conductivity, thermal conductivity, and mechanical properties [6–8].

Researchers have primarily focused on incorporating Ti3C2Tx with polymers or other nanomaterials to fabricate Ti3C2Tx composite fibers using scalable wet spinning techniques [9–11]. Gu et al. [12] employed wet spinning to prepare Ti3C2Tx/polyrotaxane composite fibers, which demonstrated the best overall performance when the mass fraction of Ti3C2Tx was 85 wt%, including a tensile strength of 188.7 MPa and an electrical conductivity of 247.5 S cm−1. He et al. [13] fabricated Ti3C2Tx/reduced graphene oxide composite fibers via wet spinning, having optimal tensile strength (110.7 MPa) and electrical conductivity (743.1 S cm−1) with the Ti3C2Tx content of 60 wt%. Although the addition of polymers and other nanomaterials enhances the mechanical properties of Ti3C2Tx composite fibers, their inherent non-conductivity or poor conductivity, along with the interface mismatch with Ti3C2Tx, induces significant electron scattering that severely hampers electron transport [14–16]. As a result, the failure of the composite fibers to achieve the anticipated breakthrough in electrical conductivity occurs despite a high loading of Ti3C2Tx [17, 18].

Studies have shown that the issues of introducing non-conductive materials and interface mismatch can be effectively avoided through the fabrication of Ti3C2Tx fibers by sole assembling Ti3C2Tx nanosheets, which enable a breakthrough in the electrical conductivity of Ti3C2Tx fibers [19, 20]. However, the weak interlayer interactions between Ti3C2Tx nanosheets pose a significant challenge of poor mechanical properties and easy brittleness for Ti3C2Tx fibers during the assembly process [21, 22]. Some efforts have been made to enhance the mechanical properties of Ti3C2Tx fibers by reinforcing interlayer connectivity with the hydrogen and ionic bonding [23, 24]. Zhang et al. [24] used an acetic acid aqueous solution as a coagulation bath, i