Abstract
The susceptibility of nickel to environmentally assisted cracking was investigated at potentials that are relevant to primary batteries which utilize a electrolyte. Slow strain rate tests were performed on Ni under conditions which simulate exposure of Ni grid supporting the Li anode, Ni grid supporting the cathode, and exposure to the vapor phase above a electrolyte. A mixture of transgranular and intergranular cracking is observed only when polycrystalline Ni is galvanically coupled to Li or polarized to potentials equal to or below 0.0 V vs. a reference electrode. Under both of these circumstances, zero valent Li is produced from the cathodic reduction of a film which forms on exposed Ni surfaces. A Li‐induced embrittlement mechanism is proposed whereby (i) is precipitated from solution at fresh crack tips, (ii) solid Li metal is formed from cathodic reduction of , (iii) Li promotes initiation of cracks at the Ni surface, and (iv) crack advance occurs at sufficiently high rates to preclude Li diffusion into the Ni ahead of the crack tip, implying a surface‐induced cracking process.