Sandwich-Type Si@C/rGO Composite Stabilized by Polyetherimide-Derived Interface with Efficient Lithium Storage and High Rate Performance

The essential characteristics between highest theoretic capacity and intrinsic volumetric changes hinders the applicable development of Si on high energy/power lithium ion batteries. A novel strategy of building moderate interface linkage combined with preferential three-dimensional structure is put forward by anchoring silicon to conductive matrix by controllable conjugated polar interaction and functional group interaction in our study. A sandwich Si-containing composite of Si@C/rGO with robust polyetherimide "Electron Bridges" is obtained. Polyetherimide is strategically introduced as electron bridges and cross links between conductive matrix and Si nanoparticles with the formation of carbon nanoshell and controllable interface linkage. Beneficially, the architecture effectively provides more electron channels to maintain electrical connectivity, and alleviates the structure collapse to ensure the utilization and the stabilization of silicon materials. This Si@C/rGO anode material exhibits excellent cycling performance with a high reversible capacity of 2048.7 mAh g−1 after 100 cycles. The Coulombic efficiency approaches to 99.8%, and the average capacity loss is only 0.103% per cycle over 500 cycles at 5 C. The optimized confluence of robust interface bonding, stable mechanical structure and excellent electronic connectivity provides a feasible strategy to obtain ultra-long-life silicon anode materials.