(714g) Minimal Surface Co-Continuous Silicon Composites for Enhanced Lithium-Ion Batteries : A Chemo-Mechanical Study

Silicon (Si) anodes are heralded for their potential in lithium-ion batteries, offering a high theoretical capacity (4200 mAh/g) and low working potential. However, Si undergoes substantial volume variations (~300 vol%) during cycling which leads to mechanical degradation and material loss, adversely affecting battery performance. Efforts to mitigate this include use of composites and nanostructures, which decrease active material loading or include complex synthesis routes. Alternatively, co-continuous composite architectures with conductive backbones and thin coatings of Si have proven promising for balancing power/energy density with mechanical integrity. The micro-architecture, and particularly curvature distributions in these co-continuous constructs play a key role in mediating the mechanical, and in turn electrochemical performance and durability of these systems. This study utilizes fully coupled chemo-mechanical simulations and targeted experimental validations to investigate the intricate relationship between the electrode microstructure and electrochemical and mechanical behaviors. Particular attention is given to minimal surface morphologies such as spinodal and gyroid structures, because of recent advances in their synthesis at scale. We quantify the concentration, stress, and strain energy density profiles to analyze capacity retention, cracking, and delamination respectively, and demonstrate that minimal surface structures can provide tremendous advantages for electrode battery design. Complementary experiments are performed to corroborate computational findings with real-world behaviors, focusing on faradaic reactions, rate-capacity effects, and durability. This integrative study not only underscores the significance of electrode design in enhancing Si anode functionality but also offers a systematic approach for material optimization in lithium-ion batteries, thereby contributing a vital tool for advancing battery technology through informed morphological tailoring.