Microstructure Engineering of Nickel Coatings via Propynol Additive Tailoring: Stress-Corrosion Synergy in Battery Steel Shell Applications

This study systematically investigates the dual effects of propynol additive concentration (0.06–0.22 g l −1 ) on the internal stress modulation and corrosion resistance enhancement of electrodeposited nickel coatings for battery steel shells. Propynol induces progressively increasing tensile stress through lattice distortion and elevated dislocation density. A critical concentration threshold of 0.10 g l −1 optimizes the stress-corrosion balance, yielding maximal corrosion resistance via preferential Ni(111) orientation and refined grain structure. Beyond this threshold, Ni(100) dominance emerges, exacerbating surface roughening and pitting corrosion. The mechanistic interplay between grain boundary dislocation accumulation, low-energy crystallographic faceting, and passivation stability is quantitatively correlated with battery performance metrics. This work establishes a microstructure-property framework for designing hierarchical nickel coatings in energy storage systems.