Graphene-Based Phosphorus-Doped Carbon as Anode Material for High-Performance Sodium-Ion Batteries

Abstract

Graphene-based phosphorus-doped carbon (GPC) is prepared through a facile and scalable thermal annealing method by triphenylphosphine and graphite oxide as precursor. The P atoms are successfully doped into few layer graphene with two forms of P–O and P–C bands. The GPC used as anode material for Na-ion batteries delivers a high charge capacity 284.8 mAh g−1 at a current density of 50 mA g−1 after 60 cycles. Superior cycling performance is also shown at high charge−discharge rate: a stable charge capacity 145.6 mAh g−1 can be achieved at the current density of 500 mA g−1 after 600 cycles. The result demonstrates that the GPC electrode exhibits good electrochemical performance (higher reversible charge capacity, super rate capability, and long-term cycling stability). The excellent electrochemical performance originated from the large interlayer distance, large amount of defects, vacancies, and active site caused by P atoms doping. The relationship of P atoms doping amount with the Na storage properties is also discussed. This superior sodium storage performance of GPC makes it as a promising alternative anode material for sodium-ion batteries.