High-performance free-standing LTO/CNT Anodes: Overcoming the dispersion-conductivity trade-off via tailored surface chemistry for advanced full-cell architectures

Abstract

The development of high-energy-density and flexible lithium-ion batteries (LIBs) requires binder-free, free-standing electrodes that eliminate inactive components such as metallic current collectors and polymeric binders. Carbon nanotubes (CNTs) provide an ideal conductive framework. However, achieving both uniform dispersion and high conductivity in CNT-based frameworks remains challenging due to CNT aggregation and surfactant-related trade-offs. Additionally, lithium titanate (LTO) anodes suffer from interfacial instability and continuous lithium inventory (LLI) loss. To address these challenges, this study introduces a dual-surfactant dispersion strategy using polyvinylpyrrolidone (PVP) and cetyltrimethylammonium bromide (CTAB) to overcome the CNT dispersion-conductivity trade-off while simultaneously enhancing LTO interfacial stability. Upon pyrolysis, the surfactants are converted into a nitrogen-doped carbon (NC2) layer that preserves CNT conductivity and passivates LTO, suppressing electrolyte decomposition and improving interfacial transport. As a result, the P−CNT/LMO@NC2−CNT/LTO full cell exhibits exceptional electrochemical performance, achieving a high gravimetric energy density (GED) of 150 Wh/kg over 200 cycles, significantly outperforming conventional LMO/Al@LTO/Cu configurations (10 Wh/kg). By integrating optimized dispersion control, tailored interfacial chemistry, and scalable electrode architectures, this work presents a sustainable and high-performance strategy for next-generation flexible LIBs. © 2025 Elsevier Ltd