Boosting the Sodiation Kinetics of Sn Anode Using a Yolk–Shell Nanohybrid Structure for High‐Rate and Ultrastable Sodium‐Ion Batteries
Hyojun Lim, Seungho Yu, Wonyoung Chang, Kyung Yoon Chung, Wonchang Choi, Sang‐Ok Kim
Abstract
Abstract Metallic Sn (Tin) is a promising anode material for Na‐ion batteries owing to its high theoretical capacity of 870 mAh g −1 . However, its large volumetric changes, interfacial instability, and sluggish sodiation kinetics limit its practical applications. Herein, a hierarchical yolk–shell nanohybrid composed of an Sn yolk and a Carbon/Silicon oxycarbide (C/SiOC) bilayer shell is prepared via the simple pyrolysis of a silicone oil dispersion containing an Sn precursor. The multifunctional bilayer helps boost sodiation kinetics by providing conductive pathways, enhancing the reversible capacity through surface capacitive reactions, and stabilizing the electrode/electrolyte interface. Abundant void interspaces inside the yolk–shell structure accommodate large volume changes of the Sn yolk. The Sn@C/SiOC nanohybrid demonstrates high specific capacity (≈500 mAh g −1 at 1 A g −1 ), remarkable rate performance up to 10 A g −1 , and ultrastable cyclability (91.1% retention after 1500 cycles at 5 A g −1 ). This yolk–shell nanohybrid structuring can guide the development of various high‐capacity anodes for energy storage applications.