Facile synthesis of Co2P via the reduction of phosphate with KBH4 for nickel-based rechargeable batteries

Crystalline Co2P is synthesized via a green and effective method based on the reduction of phosphate with KBH4. Various analytical techniques such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy and energy-dispersive spectroscopy instrument are employed to characterize the obtained Co2P. Moreover, it is electrochemically used as an anode material for nickel-based rechargeable batteries and compared with amorphous Co-P prepared by chemical reduction. Co2P electrode presents superior electrochemical properties such as discharge capacities, cycle stability, and rate capability to Co-P electrode. The reversible discharge capacity of Co2P electrode is about 244.1 mAh g−1 at 100 mA g−1 which can be retained after 200 cycles. Co2P electrode also shows promising high rate performance. Furthermore, cyclic voltammogram illustrates that the reversible electrochemical capacity of Co2P electrode is attributed to the redox of Co/Co(OH)2. Electrochemical impedance spectroscopy displays that the charge transfer resistance of Co2P electrode is smaller than that of Co-P electrode.