A Special Yolk–Shell Sn@C Electrode with a ‘Sn Particle Core in a Carbon Cubic Shell’ Morphology for Potassium Storage

A yolk–shell type Sn@C electrode with a unique “Sn particle in a carbon cubic shell” morphology was synthesized by a precipitation-cum-calcination method for potassium-ion battery (PIB) applications. With the aid of physical, structural, electron microscopic, and chemical characterizations, the presence of the unique morphology is confirmed in the prepared yolk–shell Sn@C electrode. Electrochemical measurements on the Sn@C electrode revealed an initial specific discharge capacity of 672 mAh g–1 with a Coulombic efficiency of 67%. The enhanced electrochemical performance of the yolk–shell Sn@C electrode was analyzed by ex situ characterization including XRD, SEM, TEM, and computational techniques. The findings indicated that the better electrochemical properties are attributed to the nanosized particles, the unique hierarchical structure, and the finding that the Sn particles can be completely reversibly alloyed with K+ ions during the electrochemical reaction. The present study and its findings can thus be instrumental in extending our understanding of the behavior of Sn-based anodes for PIB applications.