Flexible Energy-Dense Li-Ion Batteries based on Super-Lightweight and Highly Flexible Metal-Coated Fabrics

Flexible Li-ion batteries (FLIBs) are in urgent demand but the balance of flexibility and energy density of the battery is a great challenge. Hundreds of works reported flexible Li batteries fabricated by special structure design or soft materials. However, getting flexibility always leads to lower energy density because of the introduction of inactive weight or volume. Hence, we proposed a new type of flexible, super-lightweight, and three-dimensional current collector, metal-coated fabrics (MCFs). They can be employed in large-scale fabrication and roll-to-roll production. By replacing the Cu foil with Cu-coated fabrics (CuCF), the energy density is increased by 10%. MCFs also show advantages on the flexible applications. For the MCF-based pouch cell, after 1,000 bending cycles at the bending radii of 5 mm and 2 mm, the capacity retention is higher than 90%. The <i>fb</i>_FOM of the LIB made with MGFs reaches over 50, outperforming industrial flexible LIB and most reported flexible LIB made with soft current collectors. Since MCFs are prepared with cost-effective materials and a highly scalable process, they are promising, from a commercial viability point of view, to replace metal foils as current collectors in a wide variety of energy storage industries.