A soil/Vulcan XC-72 hybrid as a highly-effective catalytic cathode for rechargeable Li–O₂ batteries

We report for the first time a hybrid of soil and commercial Vulcan XC-72 carbon (labeled as soil/C) as a high-performance cathode catalyst for rechargeable lithium–oxygen batteries. A one-step mixing at room temperature is used to synthesize the soil/C hybrid, in which soil particles (0.5–5 μm) play a role of void volume expanders (VVE) so that the Vulcan XC-72 carbon (∼100 nm) area is fully exposed for the deposition of the discharge product. Meanwhile, the outer & inner catalytic sites of carbon particles are sufficiently utilized. When used as a cathode catalyst for rechargeable lithium–oxygen batteries, the soil/C hybrid exhibits a large discharge capacity (7640 mA h g⁻¹), robust cyclability (100 cycles at 0.2 mA cm⁻²) and superior rate capability. This high performance is not inferior to noble metal containing catalysts. Therefore, soil as a low cost and metal-free VVE in the soil/C hybrid catalyst is promising in the application of rechargeable Li–O₂ batteries.