Conformal MXene surface engineering enables ultra-low-energy fibre-laser powder bed fusion of PEEK composites

Polyetheretherketone (PEEK) is attractive for patient-specific load-bearing implants, but its low absorption at near-infrared radiation (NIR) fibre-laser wavelengths and narrow processing window make powder bed fusion challenging. Here, Ti3C2Tx MXene nanosheets were conformally assembled on PEEK particles by electrostatic adsorption to construct Ti3C2Tx-sheathed powders with improved NIR absorption, heat transfer, and flowability. The modified powders enable stable multilayer fibre-laser powder bed fusion (f-LPBF) at ultralow volume energy densities. For PEEK/M1, the required energy density was reduced from 26.667 to 0.333 J⊕mm−3, representing a 98.75% reduction relative to pristine PEEK, while maintaining a slightly expander processable window and suppressing carbonisation-induced instability. The printed S-PEEK/M1 composites showed enhanced interlayer fusion, smoother surfaces, increased crystallinity, and a transcrystalline microstructure, resulting in a tensile strength of 71.71 ± 5.06 MPa, a flexural strength of 87.35 ± 8.02 MPa, and a Vickers hardness of 39.78 ± 3.22 HV. This work demonstrates a powder-level MXene engineering route that couples optical-thermal processability with mechanical reinforcement, providing a general strategy for high-throughput f-LPBF of high-performance polymer composites for biomedical and engineering applications.