Architectural reconfiguration of foil-dependent cathodes via percolating carbon nanotube scaffolds

초록

Conventional lithium-ion battery electrodes rely on metallic current collectors and polymeric binders to ensure interparticle contact and reduce resistance. However, such foil-dependent architectures are inherently incompatible with repeated mechanical deformation, leading to delamination and performance degradation. Here, we report a single-walled carbon nanotubes (SWCNTs)-integrated collector-free (CNT-CF) electrode enabled by monodispersed SWCNTs dispersion. The CNT-CF electrode is fabricated by homogenizing the active material with the SWCNTs dispersion, followed by slurry casting onto a substrate and drying to form a dense self-supporting electrode, while eliminating both metallic foils and polymeric binders. Due to their high aspect ratio (> 10,000), SWCNTs form a continuous three-dimensional percolating framework that conformally wraps active material particles, establishing line-contact-based electronic pathways throughout the electrode. This interconnected scaffold homogenizes electron distribution, mitigates localized chemo-mechanical stress accumulation, and suppresses electrode-level degradation. A dense and self-supporting CNT-CF electrode is achieved with only 1.5 wt% SWCNTs, delivering a high mass loading of similar to 11.1 mg cm(-2) and an areal capacity of similar to 2.19 mAh cm(-2) while maintaining an electrode-level volumetric energy density exceeding similar to 2500 Wh L-1. Furthermore, the CNT-CF electrode retains over 93% of its initial capacity after 1000 bending cycles without delamination. This work provides a practical pathway toward lightweight, flexible, and high-energy-density lithium-ion batteries.

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