In contrast to graphene, graphene oxide (GO) is readily disperse in aqueous electrolytes and can be reduced along with nickel and iron metal ions. While others had incorporated graphene in Ni-Fe deposits, no previous studies have addressed the role of GO particles on metal deposition. Ni-Fe is characterized by the anomalous codeposition behavior where there is a tendency of more Fe to be deposited than Ni even though there is an excess of Ni ions in the electrolyte. This behavior has been modeled assuming adsorbed intermediates. Here, the influence of GO on the deposit composition, structure and anomalous codeposition effect is investigated. The deposits were galvanostatically electrodeposited from a boric acid-sulfamate electrolyte at pH 2 containing commercial graphene oxide platelets. Two different cell configurations were examined:1) a rotating cylinder electrode (RCE) and 2) a copper mesh. The rotating cylinder as a working electrode was used in order to investigate mass transport. The copper mesh working electrode was placed in close contact to a flat bottom pH probe in order to examine the local pH change. The addition of GO to the electrolyte had an effect on the deposit composition and the local pH change (Fig 1). The deposit composition had either more Ni or remained the same compared to an electrolyte without GO on the RCE electrode at electrode rotation rates of 372 and 1000 rpm (Fig 1 (a) and (b)). The larger Ni content in the deposit was due to an enhanced Ni partial current density in the presence of GO. The local pH during the deposition on the mesh electrode with vigorous electrolyte stirring increased the local pH (Fig 1(c)). The composition behavior is similar to the results from the RCEs, with higher Ni content in the presence of GO. The local pH increase when GO was present is considered a factor that drives the enhanced Ni content, that may be a consequence of changes in adsorbed hydrogen. GO was not incorporated into the deposit; however, it had a dramatic effect on the morphology. There was less micro-cracks when GO was present in the electrolyte suggesting less adsorbed hydrogen. Thus, GO influenced the adsorbed intermediates making the electrodeposition less anomalous and having less cracks. Acknowledgement: This work was supported in part by the AESF Foundation. Figure 1. The influence of GO in the electrolyte during Ni-Fe electrodeposition (a) composition on a RCE, rotating rate (a) 372, (b)1000 rpm and (c) local pH measurements on a mesh electrode under vigorous stirring, 30 mA/cm2. Figure 1