Structural confinement engineering of current collectors enables the development of durable SiOx anodes for lithium-ion batteries

Abstract

In this study, an anode with SiO_x embedded within a pressed Cu mesh (SPCM) was developed to mitigate structural degradation and interfacial instability during cycling. The four-sided confinement of the pressed Cu mesh mechanically supported the active material, suppressing volume expansion and enabling multidirectional electron pathways for uniform charge distribution. SPCM, incorporating 0.40 wt% single-walled carbon nanotubes (SWCNTs) (denoted as SPCM-40), further enhanced interparticle conductivity and mechanical integrity. Consequently, the SPCM-40 electrode exhibited superior cycling stability and rate capability compared with a conventional Cu-foil-based SiO_x electrode (SF), delivering an initial capacity of ∼1800 mAh g⁻¹ and an areal capacity of 3.2 mAh cm⁻². Structural and electrochemical analyses using techniques such as SEM, EDS, GITT, EIS, and XPS confirmed suppressed pulverization, improved Li-ion transport, and the formation of a LiF-rich SEI. Delamination and cracking caused the SF electrode to expand by 267% in the vertical direction, while the SPCM-40 electrode exhibited only 117% expansion. In a pouch-cell configuration with an NCM811 cathode, SPCM-40 maintained stable cycling over 100 cycles and achieved a theoretical energy density 1.4 times higher than that of the Cu-foil SiO_x electrode. This work highlights a simple yet effective current-collector engineering strategy for achieving graphite-free, high-stability SiO_x anodes for next-generation lithium-ion batteries.