具有高循环稳定性的氮硫掺杂多孔碳纳米球钠离子电池负极材料

摘要

开发高性能和低成本的负极材料对于室温钠离子电池(SIBs)的商业化至关重要.本文以葡萄糖为碳源,采用简单的水热法合成了粒径均匀且具备多孔结构的碳纳米球,并通过KOH活化和氮、硫共掺杂对其进行改性.作为钠离子电池的负极材料,该碳纳米球在20 mA g-1的电流密度下表现出高达527 mAh g-1的初始比容量,并且在500 mA g-1的高电流密度下经过1000次循环之后仍保持了95.2%的初始比容量,其循环稳定性优于大多数近期报道的钠离子电池负极材料.其优异性能来源于KOH活化和异质原子掺杂所带来的丰富的孔结构,较大的层间距和良好的导电性.%Developing high-performance and low-cost anode materials is crucial for the practical use of sodium-ion batteries ( SIBs) at room-temperature. Porous carbon nanospheres with a uniform diameter for use as SIB anode materials were synthesized by the hydrothermal treatment of glucose to obtain the spheres, and subsequent carbonization and modification with KOH activation and N, S co-doping during or after the activation using thiourea as the N and S sources. Nanospheres doped with N and S after KOH activation have a high initial specific capacity of 527 mAh g-1 at a current density of 20 mA g-1 and an excellent cycling stability with a 95. 2% capacity retention after 1000 cycles at a high current density of 500 mA g-1 . The capacity retention rate is higher than that of most of the state-of-the-art anode materials for SIBs. This good performance is attributed to the abundant micro-pores, the en-larged interlayer spacing produced by the co-doping, and the high conductivity of the carbon nanospheres.