Tailoring Self‐Catalytic N─Co Bonds into Heterostructure Architectures: Deciphering Polytellurides Conversion Mechanism Toward Ultralong‐Lifespan Potassium Ion Storage

Abstract

AbstractTransition metal tellurides (TMTes) are promising anodes for potassium‐ion batteries (PIBs) due to their high theoretical specific capacity and impressive electronic conductivity. Nevertheless, TMTes suffer from persistent capacity degradation due to the large volume expansion, high ion‐diffusion energy barriers, and the dissolution/shuttle of potassium polytellurides (KxTey). Herein, a heterostructured CoTe2 composite equipped with a self‐catalytic center (N‐CoTe2/LTTC) is developed, exploiting its low‐tortuosity tunneling, chemical tunability, and self‐catalytic properties to elevate cycling stability to new heights. Systematic experiments have verified that the elaborate N‐CoTe2/LTTC provides a short‐range and efficient electron/ion transport path, accelerates K+ diffusion kinetics, and suppresses huge volume distortion. Notably, the N─Co bonds self‐catalytic center can promote the adsorption capabilities and accelerate the conversion kinetics for KxTey under the synergistic effect of heterojunction. Consequently, the optimized N‐CoTe2/LTTC electrode delivers an ultralong‑lifespan cyclability (over 25 000 cycles at 2.0 A g−1, only 0.0019% capacity decay rate per cycle), outperforming those of reported Te‐based anodes. Finally, the N‐CoTe2/LTTC//PTCDA@450 full cell manifests impressive stability (over 4300 cycles at 2.0 A g−1). This work uncovers the impact of catalytic centers on the conversion of KxTey and provides valuable insights for rationally designing ultralong‐lifespan TMTes anodes for PIBs.