Study on microstructure and electrochemical performance of the MlNi3.55Co0.75−xMn0.4Al0.3(Cu0.75P0.25)x (x = 0-0.5) composite alloys

► All the alloy electrodes exhibit favorable activation properties. ► The cycle stability is improved due to the multiple substitution. ► The high-rate discharge capability is improved especially at high discharge current. ► The charge-transfer resistance decreases and the exchange current density increases. ► The hydrogen diffusion coefficient increases with increasing Cu-P content.