Facilely fabricating FeSe nanoparticles embedded in N-doped carbon towards promoting sodium storage behaviors

Sodium ion battery (SIB) has been recognized as the successor to lithium ion battery (LIB) owing to its inherit feature of low cost and abundant resource. The commercial graphite anodes in LIB have been demonstrated unsuitable to accommodate Na+ due to the larger ionic radius than Li+. In this work, FeSe nanoparticles embedded in N-doped carbon (denoted as FeSe/N–C) are produced by one-step solid-phase process and explored as the potential anode candidate in SIB. Such composites exhibit high conductivity and special structural durability which provide good charge transport kinetics. As expected, the FeSe/N–C electrode displays high specific capacity, excellent rate performance and ultra-stable long-term cycling stability: it delivers a reversible capacity of 468.5 mAh g−1 at 0.5C rate, and 333.9 mAh g−1 for 800th cycle at 2.0C rate; more impressively, it exhibits a 235.9 mAh g−1 at 5.0C rate during the rate capability testing. This simple synthesis procedure may open up a way to engineer other metal selenide with carbonaceous modification agents for Na+-storage considering the cost-efficient and easy-scalability.