Scalable Layer-by-Layer Stacking of the Silicon-Graphite Composite: Prelithiation Strategy of the High-Capacity Anode for Energy/Power-Dense Li Batteries

The Si anodes suffer from the repetitive buildup of the solid electrolyte interphase, electrode pulverization upon the lithiation/delithiation process, as well as the Li trapping in the alloy intermediates. Herein, a facile electrostatic self-assembly process of the Si nanosheets (SiNS) and graphite microsheets (GMs) is proposed as a viable high-capacity composite anode. Upon the appropriate interfacial tailoring, the SiNS/GMs composite not only guarantees the intimate contact mode between the sand-milled Si nanosheets and the positively charged graphite sheets but also renders the enhanced electrode conductivity and high-rate performance (886.2 mAh g–1 at current density of 5 A g–1). In addition, the prelithiated SiNS/GMs (Pre-SiNS/GMs) are fabricated by spraying stabilized lithium metal powder (SLMP) at the predetermined amounts onto the electrodes, contributing to the improved initial Coulombic efficiency (ICE) of the half cell (99%). As the Pre-SiNS/GMs anodes are assembled with the diverse commercial cathodes, the full cell models reveal the balanced cycling endurance and the high gravimetric energy/power densities.