Synthesis of porosity controllable nanoporous silicon with a self-coated nickel layer for lithium-ion batteries

Silicon (Si) is a promising anode material for next-generation high-performance lithium-ion batteries (LIBs) owing to its large theoretical capacity. However, its application is limited due to several issues including large volume expansion during the charge–discharge process, causing mechanical pulverization and low electrical conductivity. Herein, we report a scalable method to synthesize nanoporous Si using Al–Si–Ni amorphous precursor alloys. The nanoporous structure is fabricated by selective phase dissolution of crystallized alloys, wherein the pore and ligament sizes in the nanoporous structure are controlled. A thin Ni layer is formed on the surface of the Si ligament by a spontaneous reaction during selective phase dissolution, such that the nanoporous structure fabrication and formation of the conductive coating layer occur simultaneously. The Ni-coated nanoporous Si delivers a high initial coulombic efficiency and high reversible capacity after 500 cycles. This study offers a novel strategy for synthesizing nanostructured Si anode material for next-generation LIBs.