石墨通常用作锂电池的负极材料,随着锂电池需求扩大和天然石墨产量降低,高质量负极材料的可持续性供应压力不断增加,开发可替代的高性能合成石墨作为锂电池负极材料具有重要意义。以太西无烟煤为原料,通过SiO2催化、氧化微扩和活化造孔制备出结构稳定且具有分级孔结构的多孔无烟煤基石墨,并分析其作为锂电池负极材料的电化学性能。结果表明:随着催化剂SiO2含量的增加,煤基石墨的石墨化程度和石墨晶体结构有序化程度逐渐提高;氧化微扩处理后,煤基石墨层间距增大且中孔和大孔数量增多,石墨晶体结构有序化程度降低并产生了大量缺陷结构;活化造孔后,煤基石墨微观形貌改变明显,其微孔数量增多,孔隙结构发育良好。在SiO2质量分数为20%时,无烟煤基石墨石墨化程度高达89.3%,氧化微扩处理后石墨微晶层间距由0.33632nm扩大至0.33809nm,比表面积由4.17120m2/g扩大到29.47100m2/g,而活化造孔后,煤基石墨孔隙结构进一步发育,微孔比表面积由2.94990m2/g扩大至8.15060m2/g。在SiO2质量分数为20%时,多孔无烟煤基石墨在0.1C倍率下首次可逆比容量和库伦效率分别为298.0mAh/g和67.41%。多孔无烟煤基石墨在1C倍率下循环110次后,可逆比容量为234.1mAh/g,容量保持率为95.1%,且库伦效率始终接近100%。无烟煤在石墨化过程中经SiO2催化、氧化微扩以及活化造孔后可形成具有较好电化学性能的多孔煤基石墨,可成为潜在的高性能锂电池负极材料。

Graphite is widely used as a negative electrode material in lithium-ion batter-ies. With the increasing demand for lithium-ion batteries, coupled with the declining production of natural graphite, has the sustainable supply pressure of high-quality negative electrode materi-als continues to increase. Hence, there is a need to develop high-performance synthetic graphite as an alternative to natural graphite. Porous anthracite-based graphite with a stable and hierarchi-cal pore structure was synthesized from Taixi anthracite using SiO2 catalysis, oxidation-induced micro-expansion, and pore formation through activation. The electrochemical properties of the porous anthracite-based graphite as a negative electrode material subsequently were analyzed. The results show that with the increase of SiO2 content in the catalyst, the degree of graphitiza-tion and the orderliness of graphite crystal structure of coal-based graphite gradually increase; af-ter the oxidation-induced micro-expansion treatment, the spacing of coal-based graphite layers and the number of medium and large pores are enlarged. The ordering degree of coal-based graphite crystal structure decreases, generating a significant amount of defect structures. After the activation pore formation, the micromorphology of coal-based graphite changes significantly, leading to an increase in the number of micropores and a well-defined pore structure. With the mass fraction of SiO2 of 20%, the graphitization degree of anthracite-based graphite reaches 89.3%, and the spacing between graphite crystallite layers increases from 0.336 nm to 0.338 nm following oxidation-induced micro-expansion treatment. The specific surface area increases from 4.171 m2/g to 29.471 m2/g. After activation pore formation, the pore structure of porous anthracite-based graphite further developes significantly, resulting in an increase in the specific surface area of micropores from 2.949 m2/g to 8.150 m2/g. With the mass fraction of SiO2 of 20%, the porous anthracite-based graphite exhibites an initial reversible specific capacity of 298.0 mAh/g and a coulombic efficiency of 67.41% at a multiplying of 0.1 C. After cycles at a multiplying of C, the reversible specific capacity measures 234.1 mAh/g, retaining 95.1% of its capacity, with the coulombic efficiency consistently remaining near 100%. Anthracite, after undergoing SiO2 catalysis, oxidation-induced micro-expansion, and activation pore formation dur-ing the graphitization process, can yield porous anthracite-based graphite with favorable electro-chemical properties.