Structure-controlled Co-Al layered double hydroxides/reduced graphene oxide nanomaterials based on solid-phase exfoliation technique for supercapacitors.

High-efficient nanosheets exfoliation and ordered controlled stacking are in urgent need of work for electrochemistry application. Here, we have developed a high-efficient and environmentally-friendly solid-phase method for the exfoliation of Co-Al layered double hydroxide (Co-Al LDH) and graphene oxide (GO). Meanwhile, we found that there is a dynamic structure evolution in the self-assembly process between Co-Al LDH-NS and GO-NS and new theoretical structure models were proposed. With the reduction treatment, the electrochemical test results show that Co-Al LDH/rGO-3 with ideal tiling structure has better electrochemical performance, which provides a specific capacitance of 1492 F g-1 at 1 A g-1 and remains the capacitance retention at approximately 94.3% after 5000 cycles. Moreover, an energy density of 44.6 Wh kg-1 is obtained at a power density of 799.6 W kg-1. The proposed method and the structure-relationship are practically applicable for other 2D materials in the asymmetric supercapacitors.