基于煤炭开发新型碳纳米材料，用于增强过渡金属氧化物电化学性能，构筑高比容量、高稳定性锂离子电池负极材料具有巨大的应用潜力。以宁夏太西无烟煤为碳质前体，采用高温石墨化-化学氧化策略制备得到煤基氧化石墨烯(CGO)，并以多孔泡沫镍为3D支撑骨架和集流体，依次以含铁的DMF/H2O混合溶液和CGO水溶液为电解液，通过二次原位电沉积技术构建了煤基石墨烯/三氧化二铁(CG/Fe2O3)自支撑复合材料。利用场发射扫描电子显微镜(FESEM)、X射线衍射仪(XRD)、拉曼光谱(Raman Spectra)等手段对产物的形貌结构和物相组成进行了表征。结果表明，DMF与H2O的体积比为1∶1时，所制备的Fe2O3自支撑材料呈鹿角状结构;CGO的质量浓度为0.1 mg/mL时，所制备的CG/Fe2O3-1复合材料呈现分级多孔自支撑结构。将CG/Fe2O3-1自支撑复合材料直接作为锂离子电池负极，在1.0 A/g大电流密度下，具有1 156 mA·h/g的高可逆容量，容量保持率达88.9%;当电流密度提升至5.0 A/g时，容量仍可保持在1 074 mA·h/g左右，展现出优异的倍率性能。电荷储存机理分析表明，CG/Fe2O3-1复合电极的电容主要源于电池充放电过程中CG产生的双电层电容以及Fe2O3氧化还原反应产生的赝电容贡献。这种出色的储锂性能归因于分级自支撑负极的宏观设计，其赋予CG/Fe2O3-1更加稳定的空间结构和通畅的Li+传输通道，能够有效改善Fe2O3充放电过程中的体积变化，加速锂化/脱锂动力学。

The development of new carbon nanomaterials from coal has great application potential in enhancing the electrochemical performance of transition metal oxides to fabricate electrode materials for lithium-ion batteries (LIBs) with high specific capacity and high stability.Herein,the coal-based graphene oxide (CGO) was developed through a combined strategy of high temperature graphitization and chemical oxidation using Taixi anthracite as a carbon precursor,and then the coal-based graphene/ferric oxide (CG/Fe2O3) structures were constructed via electrochemical deposition method with nickel foam as substrate.With the composites directly served as a free-standing anode of LIBs,the high reversible capacity of 1156 mAh/g can be achieved at a high current density of 1.0 A/g,and the capacity retention is 88.9%,when the current density is increased to 5.0 A/g,the capacity can still be maintained at about 1 074 mAh/g,showing a better rate performance and cycling stability than Fe2O3.The analysis of the charge storage mechanism shows that the capacitance of the CG/Fe2O3-1 is mainly contributed by the electric double-layer capacitance generated by CG and the pseudocapacitance generated by the Fe2O3 redox reaction during the charging and discharging process.The remarkable lithium storage capacity of CG/Fe2O3 can be ascribed to the exquisite design of three-dimensional hierarchical architecture,which endows it with a highly interpenetrated porous conductive network and more stable spatial structure,provide more accessible electrode/electrolyte interfaces for effective Li+ and charge transport,accelerating the kinetics of lithiation/delithiation.Overall,the present study provides a useful insight into the development of coal-based graphene composites used as advanced electrode materials for LIBs.

1 实验部分

   1.1 试剂和原料

   1.2 煤基氧化石墨烯的制备

   1.3 Fe2O3自支撑材料的制备

   1.4 CG/Fe2O3自支撑复合材料的制备

   1.5 形貌结构表征

   1.6 电化学性能测试

2 结果与讨论

   2.1 Fe2O3的形貌和物相分析

   2.2 CG/Fe2O3的形貌和物相结构分析

   2.3 CG/Fe2O3自支撑材料的电化学储锂性能

   2.4 CG/Fe2O3自支撑材料的储锂动力学

3 结论