石油焦炭基储钠材料层间距扩大与闭孔研究

Increasing the interlayer spacing and generating closed pores to produce petroleum coke-based carbon materials for sodium ion storage

石油焦(PC)含碳量高,成本低,是一种有价值的钠离子电池(SIB)负极前驱体。易石墨化石油焦基炭的微晶态和孔隙结构的调控对于产生丰富的Na^(+)存储位点至关重要。本研究采用前驱体转化策略,通过酸氧化引入大量氧官能团,然后使用高温炭化分解氧官能团,重新排列碳微晶,从而扩大碳层间距,使石油焦基炭形成丰富的闭孔,大幅提高了平台区Na^(+)的储存能力。优化后的样品在0.02 A g^(-1)下可提供356.0 mAh g^(-1)的可逆容量,其中约93%容量低于1.0 V。恒流间歇滴定技术(GITT)和原位X射线衍射(XRD)表明,低电压平台区钠的储存能力涉及层间插入和闭孔填充过程的共同贡献。本研究提出了一种利用低成本和高芳香性的前驱体开发高性能炭基负极的综合方法。

Petroleum coke(PC)is a valuable precursor for sodium-ion battery(SIB)anodes due to its high carbon content and low cost.The regulation of the microcrystalline state and pore structure of the easily-graphitized PC-based carbon is crucial for creat-ing abundant Na^(+)storage sites.Here we used a precursor transformation strategy to increase the carbon interlayer spacing and gener-ate abundant closed pores in PC-based carbon,significantly increasing its Na^(+)storage capacity in the plateau region.This was achieved by introducing a large number of oxygen functional groups through mixed acid treatment and then using high-temperature carbonization to decompose the oxygen functional groups and rearrange the carbon microcrystallites,resulting in a transition from open to closed pores.The optimized samples provide a large reversible capacity of 356.0 mAh g^(-1)at 0.02 A g^(-1),of which approxim-ately 93%is below 1.0 V.Galvanostatic intermittent titration(GITT)and in-situ X-ray diffraction(XRD)analysis indicate that the sodium storage capacity in the low voltage plateau region involves a joint contribution of interlayer insertion and closed pore filling processes.This study presents a comprehensive method for the development of high-performance carbon anodes using low-cost and highly aromatic precursors.