Lifetime extension of aged Li-ion prismatic batteries via mechanical constraints

<h2>Summary</h2> This study investigates the role of mechanical constraints in enhancing the performance and longevity of calendar-aged lithium-ion batteries (LIBs). By analyzing their cycling behavior under constrained and unconstrained conditions, we demonstrate that suppressing gas generation and preserving internal structural integrity are pivotal for lifetime extension. Unconstrained cycling leads to swelling, temperature rise, accelerated gas generation, and electrode delamination, culminating in the end of life (EOL) within 600 cycles for a calendar-aged cell. In contrast, applying external pressure during cycling suppresses gas generation by mitigating the side reactions responsible for gas evolution. Mechanical constraints preserve the cell's internal structure, enabling an improved relative capacity of 83% after 600 cycles and facilitating capacity recovery and lifespan extension of cells previously subjected to unconstrained cycling. These results highlight the potential of mechanical constraints for extending the operational life of LIBs and underscores the importance of proper handling of spent batteries for potential second-life applications.