A High‐Rate and Ultrastable Re ₂ Te ₅ /MXene Anode for Potassium Storage Enabled by Amorphous/Crystalline Heterointerface Engineering

Abstract The pursuit of anode materials capable of rapid and reversible potassium storage performance is a challenging yet fascinating target. Herein, a heterointerface engineering strategy is proposed to prepare a novel superstructure composed of amorphous/crystalline Re ₂ Te ₅ anchored on MXene substrate (A/C‐Re ₂ Te ₅ /MXene) as an advanced anode for potassium‐ion batteries (KIBs). The A/C‐Re ₂ Te ₅ /MXene anode exhibits outstanding reversible capacity (350.4 mAh g ⁻¹ after 200 cycles at 0.2 A g ⁻¹ ), excellent rate capability (162.5 mAh g ⁻¹ at 20 A g ⁻¹ ), remarkable long‐term cycling capability (186.1 mAh g ⁻¹ at 5 A g ⁻¹ over 5000 cycles), and reliable operation in flexible full KIBs, outperforming state‐of‐the‐art metal chalcogenides‐based devices. Experimental and theoretical investigations attribute this high performance to the synergistic effect of the A/C‐Re ₂ Te ₅ with a built‐in electric field and the elastic MXene, enabling improved pseudocapacitive contribution, accelerated charge transfer behavior, and high K ⁺ ion adsorption/diffusion ability. Meanwhile, a combination of intercalation and conversion reactions mechanism is observed within A/C‐Re ₂ Te ₅ /MXene. This work offers a new approach for developing metal tellurides‐ and MXene‐based anodes for achieving stable cyclability and fast‐charging KIBs.