The in-situ growth of Zinc-Aluminum Layered Double Hydroxides on graphene and its application as anode active materials for Zn-Ni secondary battery

Through a hydrothermal method, Zn-Al LDHs has been successfully in situ growth on graphene. The obtained LDHs/G composite was characterized by XRD, SEM and TEM. Compared with pure LDHs and LDHs-RGO compound, the as-prepared LDHs/G composite was used as modified anode active material for Zn-Ni battery followed by electrochemical performance test such as cycling performance, cyclic voltammograms (CV), electrochemical impedance spectroscopy (EIS) and charge/discharge performance. The discharge specific capacity of LDHs/G electrode remains at about 356 mAh g−1 in the whole process of 800 cycle with the retention ratio of 94.9%. Besides, the charge/discharge test at the 50th cycle shows the electrode with LDHs/G composite presents a lower charge and higher discharge plateau than that of pure LDHs and LDHs-RGO compounds. And the CV test after 50th cycle demonstrates that the use of the LDHs/G composite as the zinc anode material has a less negative reduction peak potential and a more negative oxidation peak with a peak potential difference of 0.201 V. And the EIS measurement shows the electrochemical reaction of LDHs/G electrode is the most difficult to occur with the ohmic resistance of its electrode slightly reduced by 1.239 Ω cm2 and the charge transfer resistance reduced by 4.311 Ω cm2. All the results indicate a great improvement in electrochemical performance of the modified electrode that LDHs/G as an anode material for Zn-Ni secondary battery.