Three-Dimensional Multilayered Interconnected Network of Conjugated Carbon Nanofibers Encapsulated Silicon/Graphene Oxide for Lithium Storage

Construction of three-dimensional (3D) conductive interconnected network architecture is an effective strategy to improve the performance of lithium-ion storage capability. Currently, the main challenges faced by silicon (Si) electrodes are volume change and low intrinsic electrical conductivity since the former will lead to severe particle pulverization and the latter will result in poor cycle performance. Herein, a 3D multilayer composite material featuring interconnected network structure was designed using electrospinning technique and low temperature heat treatment method. The unique structure was alternately composed of Si-encapsulated conjugated carbon nanofibers and graphene oxide (GO) layers. The conjugated carbon nanofibers network formed by polyacrylonitrile can not only shorten the ion transport path, but also alleviate volume expansion of Si during lithium ion insertion/extraction due to its well-maintained polymer elasticity. The addition of GO in the multilayer of carbon nanofibers network effectively enhanced the conductivity of the whole electrode, and greatly reduced the direct contact between Si and electrolyte. As a result, the binderless and free-standing Si-based composite electrode with maintained structural integrity effectively improved the capacity and initial Coulombic efficiency of Si anode. The composite electrode was prepared through a facile and high-yield process, showing potential commercial application value.