Structural Confinement Engineering of Current Collectors Enables Durable SiOx Anodes for Lithium-Ion Batteries

Abstract

In this study, a SiOx embedded within a pressed Cu mesh (SPCM) anode 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 which is 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 SiOx 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 such as SEM, EDS, GITT, EIS, and XPS confirmed suppressed pulverization, improved Li-ion transport, and formation of a LiF-rich SEI. Delamination and cracking led 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, the SPCM-40 maintained stable cycling over 100 cycles and achieved a theoretical energy density 1.4 times higher than that of the Cu-foil SiOx electrode. This work highlights a simple yet effective current-collector engineering strategy for achieving graphite-free, high-stability SiOx anodes for next-generation lithium-ion batteries.