▎ 摘　　要

Cobalt-Aluminum layered double hydroxide (CoAl LDH) is a hopeful electrode material due to the advantage of easy modifiability for preparing LDH-based derivatives. However, there is short of modification methods to prepare the Co-based derivatives from CoAl LDH and also short of an intuitive perspective to analyze the pseudocapacitance mechanism of CoAl LDH and its derivatives. Herein, Graphene/CoAl LDH and its derivatives including Graphene/CoS, Graphene/CoS-1, Graphene/CoOOH, Graphene/CoP were prepared by reasonably using alkali etching treatment, sulfofication and phosphorization. The specific capacitance of Graphene/CoAl LDH, Graphene/CoS, Graphene/CoS-1, Graphene/CoOOH, Graphene/CoP at 1 A g(-1) are 260.7, 371.3, 440.8, 61.4 and 122.2 F g(-1), especially. The pseudocapacitance mechanism of Graphene/CoAl LDH and its derivatives was analyzed. Due to the positive effect of sulfofication on the electrical conductivity of GO and cobalt sulfide, the Graphene/CoS and Graphene/CoS-1 exhibit the optimal electrochemical performance and superior rate capability. In addition, due to the repulsion effect between Graphene and OH-, the Graphene/CoAl LDH exhibits optimal cycling stability of 224.1% capacitance retention after 20000 cycles. Besides, the reason of terrible specific capacitance of Graphene/CoOOH is that the presence of H bond in interlayer of CoOOH inhibits the interaction between Co3+ and OH- species. Hence, not all modifications will increase the specific capacitance of the electrode materials. Overall, this work provides us with a detailed analysis of the electrochemical mechanism and correlation of CoAl LDH and its derivatives from the perspective of crystal structure and composition. (c) 2020 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.