Stress‐Induced Failure Analysis of High‐Capacity SiO_<i>x</i>/Graphite Composite Anodes

The structural evolution of silicon oxide/graphite (SiO x /Gr) composite anodes under SiO x expansion is systematically investigated to address the lack of in‐depth studies on the mechanical disparities between Si‐based materials and graphite during operation. In this work, the electrode structure evolution is evaluated with a series of composite anodes with different SiO x /Gr ratios through electrochemical performance tests and structural characterization, focusing on pore growth and solid electrolyte interphase (SEI) renewal induced by active material volume changes. The results reveal that the continuous volume change of SiO x leads to uneven stress distribution within the electrode, which further causes mechanical fatigue and structural fractures of active materials. Notably, the replacement of modified SiO x material with artificial coating improves structural integrity and cycling performance, enabling the composite anode to maintain a capacity of 373 mA h g −1 even at 1 A g −1 after 1000 cycles. These findings demonstrate that optimizing stress distribution and structural evolution is critical for enhancing the mechanical stability and electrochemical performance of SiO x /Gr composite anodes. This study provides fundamental insights into the failure mechanisms of SiO x /Gr composite anodes and highlights the necessity of rational electrode design strategies to develop high‐capacity, long‐cycle‐life anode materials for next‐generation lithium‐ion batteries.