Recent developments in advanced anode materials for sodium-ion capacitors: a mini-review

The abundant availability of sodium resources has significantly promoted the development of sodium-ion storage devices. Among them, sodium-ion capacitors (SICs), composed of battery-type anodes and capacitor-type cathodes, have garnered increasing attention due to their ability to combine the advantages of both sodium-ion batteries and supercapacitors, offering high power density, high energy density, and long cycling stability. However, a major challenge for SICs lies in the mismatch between the slow electrochemical reaction kinetics of battery-type anodes and the fast kinetics of capacitor-type cathodes, which hinders their practical application. This review systematically discusses advanced battery-type anode materials with potential applications, primarily focusing on carbon materials, metal sulfides, and metal-organic frameworks. These materials exhibit notable advantages, including high reversible capacity, excellent rate performance, and good cycling stability. Furthermore, the sodium storage mechanisms of these materials, along with various modification strategies to enhance their performance also are delved into. Finally, the existing challenges in carbon materials, metal sulfides, and metal-organic frameworks are summarized, and potential future directions for their development are proposed.