High-Surface-Area Carbon Nanotubes-Copper Composite Foils for Lighter Advanced Anodic Current Collector for Lithium-Ion Batteries

Abstract

While playing a pivotal role in battery performance, affecting energy density, cycling life, and safety, the anodic current collector of lithium-ion batteries (LIBs) is largely overlooked in the literature. Copper, the dominant material for anode current collectors, contributes to approximately 8.1% of the battery weight yet does not participate in energy storage, limiting overall energy density. Reducing weight and thickness of copper foils optimizes the gravimetric energy density of LIBs, but challenges in processability hinder the production of thinner foils. This study presents a novel fabrication method to integrate multi-walled carbon nanotubes (MWCNTs) inside copper to potentially develop a lightweight, thin, and efficient current collector. The composite is fabricated by coating MWCNTs with polydopamine (PDA), spray-depositing onto an industrial support layer, and infilling the porous nanostructure via copper electroplating. This process enables the production of composite foils with surface areas up to 400 cm²—potentially addressing industry needs for scalable, high-performance current collectors—and achieves a thickness of 4.5 µm and density of 6.4 g cm⁻³. Moreover, electrochemical performance of the material as anode current collector in half-cell battery architecture showed improvements in gravimetric capacity of up to 7.3%, with stable cycling and efficiency.