State-of-art progress and perspectives on alloy-type anode materials for potassium-ion batteries

Potassium-ion batteries (PIBs) are considered one of the most promising alternatives to lithium-ion batteries due to the abundant and widely distributed potassium (K) resources and low redox potential of K/K⁺ (−2.92 V vs. SHE). As a critical component of PIBs, the anode materials determine the electrochemical performance of the entire device. In this case, alloy-type anode materials based on the mechanism of multi-electron transfer alloying reaction have received much attention owing to their high theoretical capacities, suitable working potential, and abundant resources. However, the huge volume expansion effect generated during the cycling process seriously affects the cycling stability of alloy-type anodes for PIBs, which hinders their practical applications. To date, a series of effective modification strategies has been developed to address the above-mentioned challenges, such as nanosized structure design and hybridization with conductive substrates. Herein, we review the state-of-art progress of alloy-type anodes for PIBs and summarize their K⁺ storage mechanism, electrochemical properties, and structure-property relationship systematically.