Operational durability of three-dimensional Ni-Fe layered double hydroxide electrocatalyst for water oxidation

Water electrolysis for hydrogen and oxygen production is a key technology in next-generation energy carrier and conversion. In particular, renewable energy sources integrated water electrolysis system has emerged due to its eco-friendly and highly energy efficient process. However, inherent limitations of renewable energy sources including intermittent and unpredictable energy production restrict stable water electrolysis cell operating. Therefore, investigation on cell performance depending on various operation conditions is absolutely required. Here, we synthesized Ni-Fe layered double hydroxide (Ni-Fe LDH) electrodes and studied their oxygen evolution reaction (OER) activities under various operational conditions matching actual environmental conditions when utilizing renewable energy sources. Changes in morphology and electrocatalytic performance were systematically studied by using XRD, FE-SEM, and EIS measurement. Our results showed that operation of water electrolysis cell in an accelerated stress condition could result in changes in morphology of crystal structure of LDH, thus restricting ions to be fully utilized at active site for OER.