摘要
Despite the high potassium-ion storage of chalcogenide anodes relative to intercalation-based graphite, inhibition of their large volume change during the potassiation/depotassiation process, and stabilization of reversible electrochemical reactions to ensure efficient electron/ion transfer remain challenging. Here we report composition-tunable ternary chalcogenides that achieve highly reversible potassium-ion storage through synergistic interactions between elements. A series of Bi 2−x Sb x Se 3 ternary chalcogenide (x = 0, 0.25, 1, 1.75, 2) solid solutions with a full composition range are designed using a facile high energy mechanical milling method. Sb 2 Se 3 substituted by Bi gives rise to a chemical bond softening effect that accompanies structural transition and maintains excellent structural stability. Meanwhile, the intermediate quaternary-phase K 3 (Bi,Sb)Se 3 enables a highly reversible 12-electron transfer conversion/alloying reaction during the potassiation/depotassiation process. Various electrochemical analyses show that Bi 2−x Sb x Se 3 inherits the advantages of binary Sb 2 Se 3 (high capacity) and Bi 2 Se 3 (stability) while balancing their respective disadvantages, confirming the synergistic effect of ternary chalcogenide systems. By engineering Bi 2−x Sb x Se 3 implemented into potassium-ion based full cells, we demonstrate a high energy/power density of 76.9 W h kg −1 /1964.2 W kg −1 for batteries and 54.3 W h kg −1 /3685.7 W kg −1 for hybrid capacitors. This work illustrates how to exploit the underlying multilateral science and the relevant electrochemistry of ternary chalcogenides to achieve excellent electrochemical performance, suggesting a new avenue of anode design for potassium-ion storage.