Mild-Temperature Solution-Assisted Encapsulation of Phosphorus into ZIF-8 Derived Porous Carbon as Lithium-Ion Battery Anode

Abstract

The high theoretical capacity of red phosphorus (RP) makes it a promising anode material for lithium-ion batteries. However, the large volume change of RP during charging/discharging imposes an adverse effect on the cyclability and the rate performance suffers from its low conductivity. Herein, a facile solution-based strategy is exploited to incorporate phosphorus into the pores of zeolitic imidazole framework (ZIF-8) derived carbon hosts under a mild temperature. With this method, the blocky RP is etched into the form of polyphosphides anions (PP, mainly P5−) so that it can easily diffuse into the pores of porous carbon hosts. Especially, the indelible crystalline surface phosphorus can be effectively avoided, which usually generates in the conventional vapor-condensation encapsulation method. Moreover, highly-conductive ZIF-8 derived carbon hosts with any pore smaller than 3 nm are efficient for loading PP and these pores can alleviate the volume change well. Finally, the composite of phosphorus encapsulated into ZIF-8 derived porous carbon exhibits a significantly improved electrochemical performance as lithium-ion battery anode with a high capacity of 786 mAh g−1 after 100 cycles at 0.1 A g−1, a good stability within 700 cycles at 1 A g−1, and an excellent rate performance.