Printing‐Scalable Ti ₃ C ₂ T _x MXene‐Decorated Janus Separator with Expedited Zn ²⁺ Flux toward Stabilized Zn Anodes

Separator modification has recently blossomed as an effective strategy to enable dendrite-free Zn metal anodes. Nonetheless, the explored avenues are not conducive to mass production by far, and little attention is paid to the essence of separator regulation. Herein, a scalable Ti3C2Tx MXene-decorated Janus separator is designed by spray-printing MXene nanosheets over one side of commercial glass fibre (GF). The thus-derived MXene-GF separator affords abundant surface polar groups, good electrolyte wettability, and high ionic conductivity, which is beneficial to homogenizing local current distribution and promoting Zn nucleation kinetics. It is noted that MXene-GF displays adjustable dielectric constants with an optimized value of 53.5, offering a directional electrical field to expedite Zn-ion flux and repel anions. Accordingly, dendrite-free Zn anode equipped within symmetric cells can be achieved with MXene-GF, enabling a stable cycling for 1180 h at 1 mA cm−2 and 1200 h at 5 mA cm−2. More impressively, the assembled aqueous Zn-ion battery full cell with Janus MXene-GF separator realizes a favorable capacity retention ratio (77.9%) upon cycling for 1000 cycles at 5.0 A g−1. This strategy with scalability and effectiveness offers a new insight into high-performance metal anodes.