Abstract:
Porous Ni
0.85Se/C composite microspheres were prepared by hydrothermal selenization using porous Ni/C composites as sacrificial templates. XRD, SEM and TEM results indicated that Ni
0.85Se/C performs good crystallinity and phase purity, and it is a porous spherical structure formed by dense accumulation of Ni
0.85Se/C nanoparticles. XPS and TG curves showed that the coexisting carbon content decreased from 27.3% in Ni/C to 7.1% in Ni
0.85Se/C. The first reversible discharge capacity of Ni
0.85Se/C was 579.2 mA·h·g
−1 at the current density of 0.2 A·g
−1, and the discharge capacity becomes 812.8 mA·h·g
−1 after 100 cycles due to the contribution of non-Faraday capacity, which was far superior to the unselenized Ni/C composites when used as an anode material for liithium ion batteries. Ni
0.85Se/C had a high discharge specific capacity as an anode material for sodium ion batteries. After 50 cycles, the residual discharge specific capacity was 293.5 mA·h·g
−1. CV and EIS analysis showed that the discharge capacity of Ni
0.85Se/C was originated from the co-contribution of Faraday and non-Faraday processes, and the mass transfer resistance decreased significantly during the initial cycle due to activation, and then increased gradually.