Ni3S2 anode of sodium-ion batteries suffers severe volume changes and materials pulverization during cycling, resulting in poor cycle stability. This work selects three-dimensional porous nickel as the substrate and simultaneously controls the hydrothermal time to regulate the morphology of the Ni3S2 electrode. The results show that the three-dimensional porous Ni3S2 electrode tends to generate nanosheet arrays in a short hydrothermal time. With the increase of hydrothermal time, the nanosheet arrays partially transformed into nanotube arrays and eventually completely transformed into nanotube arrays. Due to the high stability of nanotube structure during cycling, three-dimensional porous Ni3S2 nanotube array electrode shows the best long cycle performance and rate performance. It delivers a specific capacity of 279.1 mA·h/g after 200 cycles at a current density of 100 mA/g with a retention of 53.7%, which was much higher than that of the three-dimensional porous Ni3S2 nanosheet array electrode (26.6%) and the Ni3S2 electrode with three-dimensional porous nanosheet/nanotube structure (38.7%). Even at a high current density of 1.6 A/g, the three-dimensional porous Ni3S2 nanotube array electrode still provides a specific capacity of 291.1 mA·h/g.

sodium-ion battery; three-dimensional porous; nickel sulfide; nanosheet; nanotube