In-situ reducing synthesis of MoP@nitrogen-doped carbon nanofibers as an anode material for lithium/sodium-ion batteries

Abstract

Transition metal phosphide anodes have received increasing attention for lithium/sodium-ion batteries due to their high theoretical capacities and apposite intercalation potential range. However, the mechanical stress induced dramatic volumetric expansion upon a conversion reaction mechanism has hindered the practical applications. Herein, we demonstrate a high performance anode of MoP@nitrogen-doped carbon nanofibers (MoP@NCNFs), which are prepared from an electrospinning method followed by an in-situ carbothermic self-reduction process. The well-crystallized MoP nanoparticles are uniformly distributed in the interweaving nanofibers, affording a conductive network for fast charge/ion transport and adequate buffer space for volumetric expansion. Benefit from the unique structure, the MoP@NCNFs synthesized at 800 °C delivers a reversible capacity of 840 mAh g−1 at 100 mA g−1 after 200 cycles. At 2 A g−1, longer cycling upto 1300 cycles is achieved with a capacity of 377 mAh g−1 along with a Coulombic efficiency of 99% for Li storage. And a decent performance is also available for sodium storage. Quantitative kinetics analysis confirms that the charge storage behavior is governed by pseudocapacitance, especially at high rates (75.9% at 1 mV s–1), boosting the high-rate lithium/sodium storage performance.