Tailoring nanoscale primary silicon in laser powder bed fusion for high-performance lithium-ion battery anodes

Abstract

Silicon-based anodes, utilizing nanosized silicon materials, hold great promise for the next-generation of lithium-ion batteries due to their high capacity and stable expansion. This study aims to address challenges in traditional slurry-coated anodes, such as agglomeration and low adhesive strength, through the application of laser powder bed fusion (LPBF). The process involves fabricating an Al-Si-Cu alloy layer on a Cu foil current collector, followed by dealloying to create a porous Si-Cu anode. Simulated and experimental results demonstrate successful alloy layer formation through optimized laser spot (55 μm) and powder sizes (1–5 μm). Controlled cooling produces primary Si particles ranging from 150 nm to 1 μm. The resulting microstructure enhances electrochemical performance, particularly by tailoring the size of primary Si. The resultant porous Si-Cu anode, featuring uniformly distributed primary Si (200 nm) metallurgically bonded with Cu networks, exhibits an initial coulombic efficiency of 83% and a remarkable capacity retention of 80% after 300 cycles at 2 C. In-situ and ex-situ observations confirm the crucial role of anode architecture in performance enhancement. This study elucidates the influence of the LPBF microstructure on anode performance and broadens the potential application of laser powder bed fusion in battery manufacturing.