NiCo2S4/N,S-rGO纳米复合材料的制备和电化学储钠性能

Preparation and sodium storage performance of NiCo2S4/N,S-rGO nanocomposites

NiCo2S4是一种极具发展前景的钠离子电池(SIBs)负极材料。采用简单的一步法(混合和热处理)原位合成了锚定在N、S共掺杂还原氧化石墨烯上的纳米颗粒自组装的NiCo2S4亚微米球(NiCo2S4/N,S-rGO)。XPS表明了NiCo2S4与N,S-rGO之间存在电子转移,证实了NiCo2S4与N,S-rGO之间强的协同作用。纳米粒子自组装的NiCo2S4亚微米球有效地促进了离子的扩散,N,S-rGO优异的电学和力学性能不仅提高了电极的导电性,而且有效地缓冲了充/放电过程中NiCo2S4/N,S-rGO的体积变化。NiCo2S4/N,S-rGO作为SIBs的负极材料呈现出高可逆容量,优越的倍率性能和长期稳定性(在电流密度为0.5 A/g时循环130次后仍保持了396.7 mA·h/g的高比容量。即使在电流密度为2 A/g时,经过1000次循环后比容量仍保持在283.3 mA·h/g)。研究结果为高效负极材料的设计和合成提供了新的思路。

NiCo2S4 is a promising anode material for sodium ion batteries(SIBs).In this paper,a simple one-step method(mixing and heat treatment)was used to synthesize in-situ synthesized NiCo2S4 submicron spheres(NiCo2S4/N,S-rGO)anchored on N,S co-doped reduced graphene oxide.XPS characterization demonstrated electron transfer between NiCo2S4 and N,S-rGO,which confirmed the strong synergistic effect between NiCo2S4 and N,S-rGO.The nanoparticles self-assembled NiCo2S4 spheres effectively promoted ion diffusion,and the excellent electrical and mechanical properties of N,S-rGO not only improved the conductivity of the electrode,but also effectively buffeted the large volume changes of NiCo2S4/N,S-rGO during the charge/discharge process.Benefiting from the unique nano-architecture and strong synergistic effect,NiCo2S4/N,S-rGO applied as anode materials for SIBs presented a high reversible capacity,impressive rate capability and superior long-term stability(396.7 mA·h/g at 0.5 A/g after 130 cycles,283.3 mA·h/g at 2 A/g after 1000 cycles).Those results open an interesting strategy for rational design and preparation of efficient anode materials for SIBs.