Raspberry-like hierarchical structure FeS2 decorated by dual-carbon framework as high-performance cathode for rechargeable lithium batteries

Abstract

To address the large volume variation and low lithium-ions/electronic conductivity of FeS2 cathode for rechargeable lithium batteries, we elaborately design a raspberry-like hierarchical structure FeS2 cathode decorated by dual-carbon framework. The in-situ formed disordered carbon matrix functions as a buffer to accommodate the volume change as well as an isolated layer to prevent the FeS2 nano-grains/clusters from aggregation during (de)lithiation. Meanwhile, the out shell graphene (rGO) sheets intimately wrapped on the FeS2@C microspheres surface further help to maintain the electrode structure integrity upon cycling. Moreover, the rGO sheets can effectively construct the conductive bridges for electrons transfer between each individual FeS2@C microsphere. Combining with the carbon matrix that provides the electrons conductive channels inside the hierarchical structure, a continuous three-dimensional conductive network is built, leading to accelerated charge transfer inside the electrode. In addition, the tiny FeS2 nano-grains/clusters are uniformly dispersed in the carbon matrix with interfacial chemical coupling, further favoring the structural stability and electron transportation. As a result, the FeS2@C/rGO electrode displays a high specific capacity (0.1 C: 566 mAh g−1), a remarkable cycling stability (capacity decay rate of 0.014% per cycle at 1 C), and an excellent rate capability, demonstrating a promising cathode for rechargeable lithium batteries.