Vertically Aligned Co9S8 Nanotube Arrays onto Graphene Papers as High‐Performance Flexible Electrodes for Supercapacitors

Paper‐like electrodes are emerging as a new category of advanced electrodes for flexible supercapacitors (SCs). Graphene, a promising two‐dimensional material with high conductivity, can be easily processed into papers. Here, we report a rational design of flexible architecture with Co9S8 nanotube arrays (NAs) grown onto graphene paper (GP) via a facile two‐step hydrothermal method. When employed as flexible free‐standing electrode for SCs, the proposed architectured Co9S8/GPs exhibits superior electrochemical performance with ultrahigh capacitance and outstanding rate capability (469 F g−1 at 10 A g−1). These results demonstrate that the new nanostructured Co9S8/GPs can be potentially applied in high performance flexible supercapacitors.