Abstract:

The Ni-NiO/PCNs negative electrode materials were prepared by insitu synthesis.The effects of NaCl template,annealing temperature and annealing time on the phase composition,microstructure and electrochemical properties of the negative electrode materials were investigated.It was demonstrated that Ni/PCNs,Ni-NiO/C and Ni-NiO/PCNs anode materials mainly contain Ni and amorphous C while the last two anode materials also contain NiO phase.The appropriate annealing process for Ni-NiO/PCNs anode materials is at 300 ℃ for 4 h.Ni-NiO particles in Ni-NiO/PCNs anode materials have good dispersion and maintain three-dimensional lamellar structure with average size of 27 nm and Ni-NiO re-alizes the encapsulation of amorphous C.However,too long annealing time（6 h） will lead to the over oxidation and agglomer-ation of Ni particles,while too high temperature（400 ℃） will lead to the agglomeration of particles and the disappearance of three-dimensional lamellar structure.The discharge capacity of Ni-NiO/PCNs negative electrode material is 235 mA·h/g after 5 000 cycles with current density of 1 A/g which remains 83.93% of the first cycle.The discharge capacity and capacity reten-tion rate of Ni-NiO/C and Ni/PCNs negative electrode materials are significantly lower than that of Ni-NiO/PCNs negative electrode materials after 5 000 cycles.Ni-NiO/PCNs negative electrode materials have better cycle stability,which is mainly related to their unique three-dimensional lamellar structure.

Key words: sodium ion battery, anode material, annealing, microstructure, electrochemical performance