Importance of Morphology of Layered Double Hydroxide in Electrochemical Energy Storage and Catalysis

The development of nanomaterials for energy storage and conversion has always been important. Layered double hydroxide (LDH) is a promising material due to its high capacity, tunable composition and easy synthesis. In this work, the morphology of NiCo-LDH is tuned with surfactants including sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB), and investigated the correlation between morphology and electrochemical properties. NiCo-LDH-SDS with a layered structure exhibited a specific capacitance of 1004 C g^-1 at 1 A g^-1, which is higher than that of the needle-like NiCo-LDH-CTAB (678 C g^-1) and the rod-like NiCo-LDH (279 C g^-1). Meanwhile, NiCo-LDH-SDS and NiCo-LDH-CTAB showed a reduction of 36 and 19 mV, respectively, in their overpotentials at 10 mA cm^-2 compared to NiCo-LDH. Contact angle and adhesive force measurements proved the influence of morphology on the interfacial properties that layered structure is favorable for the timely detachment of the bubbles. Therefore, rational morphology regulation of LDH can effectively alter the gas-liquid-solid interface and thereby accelerate the reaction kinetics. The connections between morphologies, bubbles releasing and electrochemical performance are well established in this work, which can be applied in the investigation of nanomaterials for energy-related activities, especially the ones concerning bubbles releasing processes.