Electrodepositing NiCo-double hydroxides with high electrochemical performance by adjusting the rheological behavior of electrolyte

Abstract

Electrodeposition is a facile and convenient method to prepare NiCo double hydroxides for binder-free electrode materials that are equipped with superior electrochemical performance. But the samples synthesized by electrodeposition exhibit monotonous nanosheets array morphology and poor durability. In this paper, we proposed a novel electrodeposition way by introducing a water-soluble polymer, i.e. polyacrylamide (PAM) with different molecular weights (Mw) into the electrolyte to manipulate the morphology and electrochemical property. By adjusting the rheological behavior of the electrolyte, the NiCo hydroxides with different morphology can be acquired as the active materials can grow along the soft template constructed by polymer chains. The morphology of the active materials varies along with the concentration and molecular weight of the polymer as well. Furthermore, amorphous phases are accompanied by the crystal during the deposition. Benefit from the unique multilevel morphology and high specific surface area, the electrodes synthesized at the electrolyte containing an appropriate concentration of polymer exhibit higher specific capacitance and longer cycling performance than that prepared in the pure water system. This work provides a novel strategy to prepare double hydroxides with diverse morphology and electrochemical performance.