Interface engineering of Si/C microparticles with Al2O3 layer enabling high-areal-capacity lithium-ion batteries

Abstract

Silicon (Si)-based anode materials have been regarded as a viable alternative to replace traditional graphite owing to its high theoretical capacity. Nevertheless, the industrial production of Si nanoparticles (Si NPs) is hindered by low tap density and inferior areal capacity. Here, the hard carbon supported Si NPs are encapsulated by soft carbon and Al₂O₃ to fabricate HC@Si@SC@A sample for high performance lithium-ion batteries (LIBs). Micrometer-sized HC serves as size regulator for Si NPs and SC serves to improve electric conductivity and suppress volume changes. With the existence of Al₂O₃, a thin and inorganic components-rich solid electrolyte interphase (SEI) has formed, greatly maintaining the stability of electrode during cycling. Therefore, the HC@Si@SC@A anode delivers an ultrahigh discharge capacity of 14.5 mAh cm⁻² at 0.2 A g⁻¹. It can show excellent performance as an anode of full cells with the NCM811 as the cathode material.