Electrolysis

But negatively charged chloride in seawater salt can corrode the positive end, limiting the system’s lifespan

The researchers discovered that if they coated the anode with layers that were rich in negative charges, the layers repelled chloride and slowed down the decay of the underlying metal.

They layered nickel-iron hydroxide on top of nickel sulfide, which covers a nickel foam core. The nickel foam acts as a conductor – transporting electricity from the power source – and the nickel-iron hydroxide sparks the electrolysis, separating water into oxygen and hydrogen. During electrolysis, the nickel sulfide evolves into a negatively charged layer that protects the anode.

https://news.stanford.edu/2019/03/18/new-way-generate-hydrogen-fuel-seawater/