Anchoring Metal-Organic Framework-Derived ZnTe@C onto Elastic Ti3C2Tx MXene with 0D/2D Dual Confinement for Ultrastable Potassium-Ion Storage

The prosperous deployments of renewable energy have stimulated the looming exploration of K-ion batteries (KIBs) for grid-scale energy storage because of their high energy density and low cost. However, lacking advanced anode materials with high theoretical capacity, fast K+ storage kinetics, and eco-friendliness discourages KIB development. Here, for the first time, ZnTe as an advanced KIB anode material with a conversion reaction mechanism (yZnTe + xK(+) + xe(-) -> yZn + KxTey) is demonstrated. The ZnTe nanoparticles are uniformly dispersed in a carbon matrix using metal-organic frameworks as starting materials, which are subsequently anchored on Ti3C2Tx MXene nanosheets, forming elaborate ZnTe@C/Ti3C2Tx (ZCT) nanohybrids. Various theoretical modeling and postmortem examinations reveal the synergistic integrations between carbon and Ti3C2Tx. Compositionally, they regulate the electronic structure of ZnTe, providing fast K+ adsorption kinetics. Morphologically, they construct a 0D/2D dual confinement, addressing the volume change of ZnTe upon cycling. Therefore, the ZCT exhibits a high capacity (408.0 mA h g(-1) at 0.1 A g(-1)) and excellent long-term cyclability (230.2 mA h g(-1) at 1.0 A g(-1) after 3500 cycles), outperforming other reported transition-metal-chalcogenides. Significantly, the ZCT-based full cells achieve a high energy density of 110.3 Wh Kg(-1), making ZCT promising for practical applications.