Elastic Graphene-Shell Architectures Enable Stress Regulation in High-Capacity Lithium-Ion Battery Electrodes

Silicon-based anodes are limited by large volume changes, stress accumulation, and sluggish kinetics during cycling. Porous electrode designs can alleviate these problems, but conventional approaches often rely on multistep processing or sacrificial pore formers. Here, hollow graphene-shell (GS) spheres are introduced as slurry-compatible pore-engineering additives. In a 5-60-5 MPa pressure cycle, the SiO_x/GS electrode shows greater thickness recovery than pristine SiO_x, with thickness-recovery indices of 4.18 and 1.24 percentage points, respectively. Individual GS particles show a largely recoverable response within the small-displacement range probed by atomic force microscopy (AFM), with an apparent modulus of approximately 114 MPa. Upon full lithiation, the through-plane thickness of the SiO_x/GS electrode increases by 15%, compared with 94% for pristine SiO_x. The SiO_x/GS electrode also retains approximately 702 mAh g^-1 after 400 cycles at 1.6 A g^-1. GS improves the performance of the tested SiO_x/graphite, Si@C, and LiNi_0.8Co_0.1Mn_0.1O₂(NCM811) formulations as well. These results demonstrate a simple, slurry-compatible strategy for accommodating electrode deformation while maintaining electrochemical performance.