High-Entropy Conversion-Alloying Anode Material for Advanced Potassium-Ion Batteries

Conversion-alloying dual-mechanism materials are considered as promising anodes for potassium-ion batteries (KIBs) owing to multielectron transfer with high theoretical specific capacity and low operating voltage, whereas large lattice strain and sluggish kinetics hinder the rate and cyclability ability. Herein, a high-entropy telluride (HET, Sb1.4Bi0.2Sn0.2Co0.1Mn0.1Te3) is proposed as an advanced anode material for KIBs. The disordered coordination environment originated from high-entropy composition assists HET to eliminate band gap, enhance K-ion adsorption capability, and lower K-ion migration barrier, thereby contributing superior electrochemical dynamics behavior. It is verified that HET stores K-ion via a conversion-alloying dual-reaction mechanism employing Sb, Bi, Sn, Co, and Mn ions as redox sites for charge compensation, where great structure stability with the suppressed volume variation can be achieved for HET benefited from high-entropy and "cocktail" effects. Robust KF-rich solid electrolyte interface film is tailored on HET via compatible KFSI-based electrolyte chemistry. Therefore, HET delivers a high initial specific capacity of 376.5 mAh<middle dot>g-1 at 50 mA<middle dot>g-1, outstanding rate performance (175.7 mAh<middle dot>g-1 at 2000 mA<middle dot>g-1), and great cycling stability with long lifespan over 500 cycles. Besides, a high-energy-density (428.8 Wh<middle dot>kg-1) K-ion full battery is assembled. This work offers a compelling avenue for achieving high-performance anode material for KIBs via a high-entropy strategy.