Designing conductive networks of hybrid carbon enables stable and long-lifespan cotton-fiber-based lithium-sulfur batteries.

In modern society, flexible rechargeable batteries have become a burgeoning apodictic choice for wearable devices. Conventional lithium-sulfur batteries lack sufficient flexibility because their electrode materials are too rigid to bend. Along with the inherent high theoretical capacity of sulfur, lithium-sulfur batteries have some issues, such as dissolution and shuttle effect of polysulfides, which restricts their efficiency and practicability. Here, a flexible and "dead-weight"-free lithium-sulfur battery substrate with a three-dimensional structure was prepared by a simple strategy. With the cooperative assistance of carbon nanotubes and graphene attached to cotton fibers, the lithium-sulfur battery with 2.0 mg cm sulfur provided a high initial discharge capacity of 1098.7 mA h g at 1C, and the decay rate after 300 cycles was only 0.046% per cycle. The initial discharge capacity at 2C was 872.4 mA h g and the capacity was maintained 734.4 mA h g after 200 cycles with only a 0.079% per cycle decay rate.