Self supported selenium doped Fe2P hierarchical microsphere arrays enabling high performance sodium ion batteries

In view of the low cost and comparable properties with lithium ion batteries (LIBs), sodium ion batteries (SIBs) are considered to be the most hopeful candidate or supplement for LIBs. To date, conversion-type transition metal phosphides (TMPs) are pursued as vital anode materials in SIBs since their high theoretical capacity and low redox potential compared to their oxides and sulfides, yet still suffer from unfavorable electrical conductivity and poor reaction kinetices. In this regard, for the first time, we put forward a self supported Fe2P hierarchical microsphere arrays with Se doping to optimize the performance of transition metal phosphides. As expected, the Se doped Fe2P (Fe2P0.8Se0.2) arrays obviously show superior performnace than bare Fe2P, delivering a high reversible capacity of 312.5 mAh g−1 at 2000 mA g−1, and sustaining a capacity of 395.1 mAh g−1 at 1000 mA g−1 experiencing 1000 cycles. Combined with the experiment and in-depth DFT calculation results, it can be concluded that the Se doping protocol could largely modulate the charge density distribution and enhance Na adsorption ability thereafter minimize Na+ diffusion energy barrier, enabling elevated electrochemical performance.