Lightweight CNT Fabric Current Collectors Enabling Silicon Anodes in High-Capacity Lithium-Ion Batteries

Abstract Conventional lithium-ion batteries (LIBs) require metallic current collectors such as copper for anodes and aluminum for cathodes, adding significant weight without contributing to the capacity. This is especially problematic for Si-dominant anodes, with mass loadings lower than 2 mg cm–2. Here, copper is replaced with lightweight, non-woven carbon nanotube fabrics (CNTfs) combined with high-capacity Si/PPAN active material to form a self-standing composite anode. This lightweight electrode delivers a capacity of 1000 mAh g–1 (normalized with respect to the total Si/PPAN/CNTf anode weight) for over 700 cycles at a current density of 1 A g–1 and can potentially boost the cell-level energy density by ∼25% when paired with commercial cathodes. Cross-sectional SEM-EDX imaging and peel tests confirm excellent interfacial contact between the Si/PPAN layer and CNTf current collector. Furthermore, the effects of increasing CNTf thickness reveal more evident SEI formation in the CNTf layer, lowering the first-cycle Coulombic efficiency. These findings demonstrate the potential of using CNTfs in high-energy LIBs, while also reducing emissions associated with metal manufacturing.