3D printed silicon-based micro-lattices with ultrahigh areal/gravimetric capacities and robust structural stability for lithium-ion batteries

Nanostructured silicon anodes have shown extraordinary lithium storage properties for lithium-ion batteries (LIBs) but are usually achieved at low areal loadings (< 1.5 mg·cm⁻²) with low areal capacity. Sustaining sound electrochemical performance at high loading requires proportionally higher ion/electron currents and robust structural stability in the thicker electrode. Herein, we report a three-dimensional (3D) printed silicon-graphene-carbon nanotube (3D-Si/G/C) electrode for simultaneously achieving ultrahigh areal/gravimetric capacities at high mass loading. The periodically arranged vertical channels and hierarchically porous filaments facilitate sufficient electrolyte infiltration and rapid ion diffusion, and the carbonaceous network provides excellent electron transport properties and mechanical integrity, thus endowing the printed 3D-Si/G/C electrode with fast electrochemical reaction kinetics and reversibility at high mass loading. Consequently, the 3D-Si/G/C with high areal mass loading of 12.9 mg·cm⁻² exhibits excellent areal capacity of 12.8 mAh·cm⁻² and specific capacity of 1007 mAh·g⁻¹, respectively. In-situ optical microscope and ex-situ scanning electron microscope (SEM) confirm that the hierarchically porous filaments with interconnected carbon skeletons effectively suppress the volume change of silicon and maintain stable micro-lattice architecture. A 3D printed 3D-Si/G/C-1||3D-LiFePO₄/G full cell holds excellent cyclic stability (capacity retention rate of 78% after 50 cycles) with an initial Coulombic efficiency (ICE) of 96%. This work validates the feasibility of 3D printing on constructing high mass loading silicon anode for practical high energy-density LIBs.