Cs600

The contents of light elements—H, C, N, O, and S—in the as-deposited NT-Ni specimens were analyzed using a combination of simultaneous carbon/sulfur determinator (CS600, LECO) and oxygen/nitrogen/hydrogen analyzer (TCH-600, LECO). The contents of other elements were also quantified using inductively coupled plasma optical emission spectroscopy (ICP-OES; OPTIMA 8300DV). The carbon and sulfur in our specimens (table S1) originate from the additives in the plating bath, i.e., 2-butyne-1,4-diol and sodium saccharin, and their contents in NT-Ni specimens are consistent with those reported previously in (49 ). Energy-dispersive x-ray spectroscopy (EDS) equipped in an FEI Talos F200X TEM was used as a supplemental method to characterize the elemental distribution at GBs in the as-deposited NT-2.9 specimen. EDS line scans showed that carbon and sulfur were uniformly distributed in the sample with no obvious segregation at the GBs (fig. S13).