煤炭的洁净加工与高效利用是国家实施能源发展战略的核心内容，而煤的材料化是实现其低碳高值化利用的重要途径之一。以自制煤基石墨为原料，采用液相氧化-热还原工艺制备三维层次孔煤基碳纳米片宏观体(CCNSs)，利用扫描电镜(SEM)、透射电镜(TEM)、低温氮气吸附仪、X射线衍射(XRD)、拉曼光谱(Raman)和X射线光电子能谱(XPS)等手段表征其微观结构，并采用恒流充放电和循环伏安测试探究CCNSs用作锂离子电池负极材料的电化学性能。结果表明，煤基石墨经液相氧化-热还原处理可制备出富含多孔结构和石墨微晶片层的碳纳米片宏观体。氧化剂用量是影响CCNSs微观结构的重要因素，通过调节氧化剂的用量可实现对CCNSs中多孔结构和石墨微晶片层结构的有效调控。当氧化剂与煤基石墨的质量比为4时，CCNSs-3材料以相互交联的类石墨烯片层为主体骨架，辅以孔径为1.5~100 nm的“微孔-中孔-大孔”层次多孔结构，共同构筑成3D层次孔煤基碳纳米片宏观体，其石墨微晶含量约为38.9%，比表面积达285.6 m2/g，且含有5.47%的氧原子掺杂。在3D层次孔结构和石墨微晶片层的协同作用下，CCNSs材料用作锂离子电池负极材料表现出良好的电化学性能，在50 mA/g电流密度下的首次可逆容量最高可达917 mA·h/g(远高于传统石墨负极材料的理论容量372 mA·h/g)，在2.0 A/g大电流密度下可逆容量仍可达300 mA·h/g，经过120次循环后容量为1 047 mA·h/g，展现出优异的倍率特性和循环稳定性，是一种比较理想的锂离子电池负极材料。

The clean processing and high-efficiency utilization of coal is the core content of the national energy development strategy,and the materialization of coal is one of the important ways to realize its high value-added utilization.Herein,three-dimensional (3D) hierarchical porous coal-based carbon nanosheets (CCNSs) with controllable structure were prepared via a liquid oxidation-thermal reduction method using pre-synthesized graphite as the carbon source.The microstructure of CCNSs was characterized by scanning electron microscope (SEM),transmission electron microscope (TEM),nitrogen adsorption-desorption,X-ray diffraction (XRD),Raman spectroscopy (Raman) and X-ray photoelectron spectroscopy (XPS),and their electrochemical performances applied as anode in lithium-ion batteries (LIBs) were further investigated via galvanostatic charge-discharge (GCD) and cyclic voltammetry (CV) tests.The results indicate that CCNSs with abundant 3D hierarchical porous and graphite microcrystalline structure can be successfully prepared by the liquid oxidation-thermal reduction method.The dosage of oxidant is an important factor affecting the microstructure of CCNSs,and the 3D hierarchical porous and graphite microcrystalline structure in CCNSs can be effectively regulated by adjusting the dosage of oxidant.When the mass ratio of oxidant to TXG is 4,the prepared CCNSs-3 exhibits a 3D hierarchical porous network structure formed by the cross-linking of graphene-like nanosheets and retains 38.9% graphite microcrystalline structure,while possesses a specific surface area of 285.6 m2/g and contains large amount of micro-meso-macroporous structure with an abroad pore size distribution of 1.5-100 nm and 5.47% oxygen doping.Due to the synergistic effect of 3D hierarchical porous structure and graphite microcrystalline structure,the CCNSs materials as anode in LIBs exhibit an excellent electrochemical performance.In particular,the optimal CCNSs electrode can deliver a high initial reversible capacity of 917 mA·h/g(higher than the 372 mA·h/g theoretical capacity of traditional graphite) at a current density of 50 mA/g,and possesses a high reversible rate capacity of 300 mA·h/g at a high current density of 2.0 A/g and the reversible capacity reaches 1 047 mA·h/g after 120 cycles,which demonstrates that the carbon material has a superior rate capability and cycling stability,suggesting that it can be a desirable anode material for LIBs.

1 实验部分

   1.1 实验原料

   1.2 3D层次孔煤基碳纳米片宏观体的结构调控

   1.3 3D层次孔煤基碳纳米片宏观体的结构表征

   1.4 电池的组装与测试

2 结果与讨论

   2.1 形貌与结构特征

   2.2 电化学性能测试

3 结论