In this study, we conducted experiments on CaC₆ for elucidating the Na-catalyzed formation mechanism and achieving rapid mass synthesis of graphite intercalation compounds (GICs). Rapidly synthesized CaC₆ was characterized by analysis of its crystal structure and physical properties. We found that the formation of the reaction intermediate Na-GIC (NaC_x, x ≈ 64) requires a larger amount of Na than is intercalated between the graphite interlayers. The requirement for excess Na may provide insights into the mechanism of Na-catalyzed GIC formation. A Na-to-C molar mixing ratio of 1.5–2.0:6 was suitable for the efficient formation of CaC₆ under heat treatment at 250 °C for 2 h, and the catalytic Na remaining in the sample was demonstrably reduced to a Na:Ca ratio of approximately 3:97. The upper critical field H_c2 was enhanced approximately three times compared to those of previous reports. Based on X-ray diffraction and experimental parameter analysis, we concluded that the enhancement of H_c2 was attributed to the disordered stacking sequence in CaC₆, possibly because of the rapid and low-temperature formation. Physical properties derived from specific heat measurements were comparable to those of high-quality CaC₆, which is slowly synthesized using the molten Li–Ca alloy method. This study provides new avenues for future research and exploration in the rapid mass synthesis of GICs as practical materials, for applications such as battery electrodes and superconducting wires.

在本研究中，我们对CaC ₆进行了实验，以阐明Na催化的形成机制并实现石墨插层化合物（GIC）的快速大规模合成。通过分析其晶体结构和物理性质，对快速合成的CaC _{6进行了表征。我们发现反应中间体 Na-GIC (NaC x} , x ≈ 64)的形成 需要比插入石墨夹层之间更多的 Na 量。对过量 Na 的需求可能有助于了解 Na 催化 GIC 形成的机制。Na-C摩尔混合比为1.5-2.0:6适合CaC _{6的有效形成}在 250 °C 热处理 2 h 下，样品中残留的催化 Na 明显减少至 Na:Ca 比例约为 3:97。与之前的报告相比，上临界场H _c2增强了大约三倍。基于X射线衍射和实验参数分析，我们得出结论，H _c2的增强归因于CaC ₆中的无序堆积顺序，可能是由于快速且低温形成的缘故。通过比热测量得出的物理性质与高质量 CaC _6相当，采用熔融Li-Ca合金法缓慢合成。这项研究为未来快速大规模合成 GIC 作为实用材料、用于电池电极和超导线材等应用提供了新的研究和探索途径。