Electrochemically exfoliated reduced graphene oxide-based freestanding separator-integrated electrode with embedded C-coated SiOx as the current collector-free anode in flexible batteries

We developed a facile, direct approach for the preparation of freestanding separator-integrated anodes with high flexibility and good capacity by mixing electrochemically exfoliated reduced graphene oxide (rGO) and C-coated SiOx (CSO) via vacuum filtration on a glass fiber separator. The type of current density applied during exfoliation significantly affected the electrochemical properties of graphene, and high electrical conductivity was obtained under the optimized conditions. The mixture of rGO and CSO exerted positive synergistic effects, including alleviated volume expansion, high specific capacity, and enhanced electrical conductivity of rGO, on battery performance, which may enable the development of current collector-free flexible Lithium-ion batteries. The optimized separator-integrated flexible anode exhibited a high reversible capacity at the fifth cycle, as well as satisfactory capacity retention over 200 cycles, which illustrates the superior rate capability and structural durability of this device.