Morphological Evolution of Sn-Metal-Based Anodes for Lithium-Ion Batteries Using Operando X-Ray Imaging.

Sn-based electrodes are promising candidates for next-generation lithium-ion batteries. However, it suffers from deleterious micro-structural deformation as it undergoes drastic volume changes upon lithium insertion and extraction. Progress in designing these materials is limited to complex structures. There is a significant need to develop an alloy-based anode that can be industrially manufactured and offers high reversible capacity. This necessitates a profound understanding of the interplay between structural changes and electrochemical performance. Here, operando X-ray imaging is used to correlate the morphological evolution to electrochemical performance in foil and foam systems. The 3D Sn-foam-like structure electrode is fabricated in-house as a practical approach to accommodate the volume expansion and alleviate the mechanical stress experienced upon alloying/dealloying. Results show that generating pores in Sn electrodes can help manage the volume expansion and mitigate the severe mechanical stress in thick electrodes during alloying/dealloying processes. The foam electrode demonstrates superior electrochemical performance compared to non-porous Sn foil with an equivalent absolute capacity. This work advances the understanding of the real-time morphological evolution of Sn bulky electrodes.