The improved anode performance enabled by Ni2P@C embedded in echinus-like porous carbon for lithium-ion battery

摘要

Nickel phosphides (Ni2P) have been proposed as advanced anode materials for a lithium-ion battery (LIB) due to its high capacity and electrochemical activity. However, the large volume expansion and poor cycling stability limit the practical applications of a Ni2P based LIB. In this work, we report a one-step strategy to prepare Ni2P@C nanoparticles embedded in echinus-like porous carbon (Ni2P@C@EPC) as a promising anode for LIB. It is demonstrated that the Ni2P@C@EPC corresponds the hexagonal Ni2P phase very well. The Raman spectrum indicates that the defective carbon is dominant in Ni2P@C@EPC. Moreover, Ni2P@C@EPC possesses a high specific surface area of 372.953 cm(2) g(-1) with an average pore size of 6.496 nm. Remarkably, the EPC plays a significant role in realizing high and stable performance by confining the reaction between Ni2P and Li+, facilitating Li+ diffusion mobility and inhibiting the volume change in charge/discharge. As a result, the Ni2P@C@EPC delivers a high specific capacity of 807.7 mAh g(-1) at 0.2 A g(-1), excellent rate capability (592.1, 455.9, 346.1, 236.4 and 160.69 mAh g(-1) at 0.1, 0.2, 0.5, 1.0 and 2.0 A g(-1)), and long cycling stability (464.8 mAh g(-1) at 0.2 A g(-1) after 100 cycles). Moreover, the structure evolution upon cycling as well as electrochemical analysis has verified the superiority of Ni2P@C@EPC anode.