Rational design of Ni/Ni2P heterostructures encapsulated in 3D porous carbon networks for improved lithium storage

Nickel phosphides are considered to be promising lithium storage host due to their high theoretical capacities. To alleviate the volume change and enhance the electrochemical reaction kinetics during electrochemical reaction process, Ni/Ni2P heterostructures are encapsuled 3D porous carbon networks. The macro/micro-pores-rich carbon networks were in-situ constructed via a freeze-drying method and subsequent pyrolysis route using NaCl as template. In the following phosphorization process, Ni/Ni2P nanoparticles were homogenously embedded in the carbon matrix. When used as anodes for lithium ion batteries, the Ni/Ni2P/porous carbon networks deliver high discharge capacity, good cycling stability as well as good rate performance. It is believed that metallic Ni and porous carbon networks significantly improve the conductivity of the electrodes. Moreover, the 3D conductive matrix can not only alleviate the volume change, but also prevent the aggregation and pulverization of Ni2P nanoparticles during the charge-discharge process.