Facile synthesis of 3D binder-free N-doped carbon nanonet derived from silkworm cocoon for Li–O2 battery

Rechargeable nonaqueous lithium–O2 batteries are considered as the most promising energy storage system for electric vehicles due to their extremely high energy density. However, the inefficient O2 diffusion, large overpotential and unwanted side reaction still restrict their specific capacity and cycle performance. This work presents a facile method to prepare a novel 3D binder-free N-doped carbon nanonet by using an economical, green and sustainable biomass—silkworm cocoon as the precursor. Li–O2 batteries with this N-doped carbon nanonet as the cathode delivered a superior specific capacity and excellent cycling stability, which attributable to the 3D porous and through structure, high specific surface area, the enhanced catalytic activity of ORR/OER arising from the incorporation of N, and the absence of binders in the electrode. Therefore, by taking advantages of the unique structure and morphology of biomass, the low-cost and green 3D binder-free N-doped carbon materials are a feasible approach for the preparation of high-performance cathode for Li–O2 battery.