A High-Rate and Ultrastable Re₂Te₅/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 Re₂Te₅ anchored on MXene substrate (A/C-Re₂Te₅/MXene) as an advanced anode for potassium-ion batteries (KIBs). The A/C-Re₂Te₅/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-Re₂Te₅ 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-Re₂Te₅/MXene. This work offers a new approach for developing metal tellurides- and MXene-based anodes for achieving stable cyclability and fast-charging KIBs.