Ultrafine Cobalt Phosphide Nanoparticles Embedded in Nitrogen-Doped Carbon Matrix as a Superior Anode Material for Lithium Ion Batteries

Ultrafine CoP nanoparticles embedded in nitrogen-doped carbon matrix derived from zeolitic imidazolate framework 67 (ZIF-67) template are first obtained. The synthesis strategy only involves a facile method in which ZIF-67 precursor is phosphided under argon atmosphere. Such novel nanostructure consists of ultrafine CoP nanoparticles and N-doped carbon matrix which greatly shorten the transport length of lithium ions, effectively buffer the volume expansion during the lithiation/delithiation process, and improve the electrical conductivity. Owing to their unique architecture characteristics, the active material exhibits a superior specific capacity of 522.6 mAh g(-1) after 750 cycles at a current density of 200 mA g(-1) and outstanding cycling stability up to 2000 cycles at a high current density of 500 mA g(-1). In addition, the active material exhibits superior rate capability.