Chemical welding of diamine molecules in graphene oxide nanosheets: Design of precisely controlled interlayer spacings with the fast Li+ diffusion coefficient toward high-performance storage application

A facile method of chemical welding was proposed to construct the diamine molecules (xDM, x  = 2, 3, 4, 6 and 8) pillared- and strained-graphene oxides (GO) with controllable interlayer spacing via the dehydration condensation reaction between GO and xDM. The interlayer spacing of xDM pillared- and strained-GO (GO-xDM) is controllably enlarged by choosing the length of xDM, which determines the pillaring effects. The GO-xDM exhibits a low diffusion barrier and ultrafast Li + diffusion dynamics due to its enlarged interlayer spacing, which leads the excellent Li + storage rate capability. The effects of interlayer spacing on Li + diffusion dynamics are clarified that GO-2DM with the interlayer spacing of 0.911 nm displays the excellent Li + storage performance and fast Li + diffusion dynamics (D Li+ =2.4 × 10 −7 cm 2 s −1 ). The GO-2DM presents a high capacity of 291.8 mAh g −1 at a current density of 0.1 A  g −1 and a high-rate capability of 120.8 mAh  g −1 at a current density of 5.0 A  g −1 . The GO-2DM//AC lithium-ion hybrid capacitor delivers a high energy density of 103.6  Wh  kg −1 at a power density of 55.8  W  kg −1 , even reaches 2777.8  W  kg −1 at a power density of 61.1  Wh  kg −1 . The approach of chemical welding provides a novel perspective for controllably enlarging interlayer spacing and designing two-dimensional (2D) energy storage materials with high-rate capability.