A polydopamine interlayer enables dual stabilization of NiFe-LDH for electrochemically and mechanically robust water electrolysis

Polydopamine (PDA)-assisted strategy develops a S-NiFe@PDA electrocatalyst with enhanced durability and activity. • PDA achieves a more stable and efficient LOM pathway and suppresses catalyst detachment under high current densities. • S-NiFe@PDA requires overpotential of only 367 mV to achieve 1.0 A cm −2 and exhibited outstanding resilience in an ADT. • S-NiFe@PDA enables stable operation at 1.0 A cm −2 for over 2100 h at room temperature in an AEMWE. Nickel-iron layered double hydroxide (NiFe-LDH) electrocatalysts have emerged as promising alternatives to precious-metal materials in alkaline water electrolysis (AWE), offering structural tunability and cost-effectiveness for a decarbonized economy. However, achieving both high activity and stability under industrially relevant conditions remains a critical challenge. In this study, we developed a polydopamine (PDA)-assisted strategy to construct an interlayer between the catalyst and substrate, resulting in a robust NiFe-based electrocatalyst (S-NiFe@PDA) with enhanced durability and activity. The PDA interlayer promotes the formation of lattice oxygen vacancies with strengthened metal-oxygen bonds and highly active Ni species, facilitating a more stable and efficient lattice oxygen-mediated mechanism (LOM) pathway. Moreover, the strong adhesion and interfacial interaction provided by the PDA interlayer effectively suppress catalyst detachment under high current densities, substantially enhancing long-term durability. The optimized S-NiFe@PDA electrode required overpotential of only 367 mV to achieve current density of 1.0 A cm −2 and exhibited outstanding resilience in an accelerated durability test (ADT), with only an 8.55% increase in overpotential after 3000 cycles, demonstrating its suitability under intermittent renewable energy inputs. When integrated into an anion-exchange membrane water electrolyzer (AEMWE), the S-NiFe@PDA enabled stable operation at 1.0 A cm −2 for over 2100 h at room temperature. This work offers valuable insights into the design of oxygen evolution reaction (OER) electrocatalysts with both high activity and industrial durability, facilitating the development of efficient water electrolysis systems. Download: Download high-res image (172KB) Download: Download full-size image The critical challenge in conventional NiFe-LDH electrocatalysts under industrially relevant conditions and our PDA-assisted strategy on endowing it robust mechanical and lattice stability.