What question did this study set out to answer?

This research aims to develop a conductive network for high-silicon-content lithium-ion battery anodes that can withstand extreme volume changes during cycling.

March 18, 2026Open Access

Directly grown carbon nanotube networks on SiOx for preserving conductivity under extreme volume change for high-silicon-content anodes

Key Points

This research aims to develop a conductive network for high-silicon-content lithium-ion battery anodes that can withstand extreme volume changes during cycling.
Developed G-SC electrode by directly growing carbon nanotubes on silicon suboxide particles.
Conducted comparative analyses with conventionally mixed CNT-SiOx composites under electrochemical conditions.
Used techniques including scanning electron microscopy and operando imaging to evaluate electrode performance.
Reduced thickness swelling by approximately 50% compared to mixed CNT-SiOx during cycling.
Achieved 77% capacity retention after 1000 cycles for NMC811|G-SC coin cells.
Demonstrated high energy densities of 309 Wh kg−1 with 90% retention after 220 cycles in single-layer pouch cells.

Abstract

This work presents a promising strategy to increase silicon content in lithium-ion battery (LIB) anodes while preserving a robust conductive network. By directly growing carbon nanotubes (CNTs) on silicon suboxide (SiO x ) particles, a high concentration of CNTs protruding from the surface of SiO x surface were localized near the SiO x particles, where electrical isolation caused by severe volume change during cycling leads to rapid degradation. Scanning electron microscopy and operando imaging revealed that the directly grown CNT–SiO x composite (G-SC) electrode exhibited reduced thickness swelling and better-preserved conductive networks during cycling, compared to the conventionally mixed CNT–SiO x composite (M-SC). Full-cell tests paired with LiNi₀.₈Mn₀.₁Co₀.₁O₂ (NMC811) cathodes under static pressure confirmed lower dimensional changes in the NMC811|G-SC cell than in NMC811|M-SC. Electrochemical analyses—including cyclic voltammetry, galvanostatic titration, electrochemical impedance spectroscopy, and galvanostatic cycling—demonstrated enhanced redox kinetics and stable reversibility for the G-SC anode. dQdV −1 analysis revealed that maintaining the conductive network is essential for suppressing capacity facing arising not only from silicon degradation but also graphite isolation. A high-loading NMC811|G-SC coin cell retained 77% of its capacity after 1000 cycles, while a single-layer pouch cell delivered high energy densities of 309 Wh kg −1 and 865 Wh L −1 with 90% capacity retention after 220 cycles. These results underscore the practicality and scalability of the G-SC architecture for next-generation high-energy LIBs with high‑silicon-content anodes. • Direct CNT growth on SiOx preserves conductive networks under extreme volume changes in LIB anodes. • G-SC electrode reduces thickness swelling by ∼50% vs. mixed CNT-SiOx during cycling. • Achieves 77% capacity retention after 1000 cycles in NMC811|G-SC coin full cells. • Single-layer pouch cell delivers 309 Wh kg −1 with 90% retention after 220 cycles. • Enhances Li + diffusion and forms stable LiF-rich SEI, suppressing Si/graphite isolation.

Directly grown carbon nanotube networks on SiOx for preserving conductivity under extreme volume change for high-silicon-content anodes

Key Points

Abstract

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