Highly Stable Silicon Anodes Enabled by Sub‐10 nm Pores and Particles

Abstract Silicon anodes offer high energy densities for next‐generation lithium‐ion batteries; however, their application is limited by severe volume expansion during cycling. Making silicon porous or nanostructured mitigates this expansion but often increases lithium inventory losses due to the inherent high surface area of nanomaterials. This study introduces a simple bottom‐up process that overcomes this limitation. The approach relies on small silicon particles (<10 nm) produced using an efficient low‐temperature plasma approach. These small building blocks are assembled into micron‐scale superstructures characterized by uniformly dispersed sub‐10 nm pores. This structure addresses both volume expansion and lithium‐inventory issues while achieving tap densities exceeding those of commercial graphite (≈1.2 g cm ⁻³ ), all while maintaining good processability. The resulting silicon‐dominant anodes achieve remarkable stability in full pouch cells with NMC811 and LFP cathodes, retaining ≈80% capacity for more than 400 cycles without pre‐lithiation, graphite blending, or pre‐cycling.