The electrochemical properties of SmMgNi4, Sm2MgNi9 and SmNi5 compounds have been investigated comparatively in this work. It is found that SmNi5 alloy electrode displays almost no discharge capacity and Sm2MgNi9 alloy electrode has a larger discharge capacity than SmMgNi4 alloy electrode at 298 K. Furthermore, the high rate discharge ability and cycle stability of Sm2MgNi9 electrode are also better than those of SmMgNi4 electrode. The improvement in electrochemical properties of Sm2MgNi9 is ascribed to suitable structural parameters and higher nickel content. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.