Carbon-Coated Mesoporous Silica Nano-Quills from Bioderived Cellulosic Templates for Low-Cost Anodes

The escalating global energy demands, driven by population growth and the electrification of transportation, have positioned rechargeable lithium-ion batteries (LIBs) as critical components in phasing out traditional fuel-based technologies. To date, several high-capacity active materials have been developed to replace current graphite-based anodes for boosting the energy density of LIBs. Silicon dioxide (SiO 2 , or silica) has emerged as a promising alternative, with a high theoretical capacity of 1965 mAh g -1 , five times higher than conventional graphite, along with a comparatively smaller volume change than elemental Si during battery cycling. In this study, we report a patented synthesis process that harnesses wood-derived cellulose nanocrystals (CNCs) to craft a unique three-dimensional (3D) silica architecture for developing low-cost LIB anodes. Our cost-effective method yields a mesoporous silica material, termed silica nano-quill (SilicaNQ), with distinctive hollow 1D arms. In addition, we propose a direct annealing strategy for transforming CNC templates into a conformal carbon coating to fabricate SilicaNQ@C powder material. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) provided a detailed exploration of the elemental composition and the bonding states at the atomic level. Anodes comprising SilicaNQ@C active material delivered a stable reversible capacity of 1030 mAh g -1 after cycling at 200 mA g -1 for 200 cycles. We performed X-ray diffraction (XRD) measurements on SilicaNQ@C half cells to identify phase changes at various state-of-charge levels and explore the evolution of interface components over cycling.