Abstract A wide variety of synthetic carbon allotropes embrace tremendous potential for energy storage applications. There have been number of reports on the synthesis of carbonaceous anode materials with lithium (Li) storage capacity larger than the theoretical limit for graphite (372 mAh/g, corresponding to LiC6). However, besides the performance, available resources and cost efficiency are obstacles that could hinder their exploitation. Here we present carbon-rich Precambrian rock “shungite” as a natural resource for a Li-ion battery anode. It is found that upon structural modification the energy density of fully lithiated “shungite” can exceed the density of graphite, becoming comparable to non-graphitizable (“hard”) carbon. High-resolution transmission electron microscopy (HRTEM) studies of modified “shungite” suggest that it consist of spatially arranged fractals of bended, curved, mono- or stacked graphene layers. By analyzing the features of 7Li Nuclear Magnetic Resonance (NMR) spectra of fully lithiated “shungite” we conclude that the enhanced storage capacity is mainly due to the presence of open edge few layered graphene flakes. We thus suggest carbon-rich “shungite” as an alternative and effective natural resource for Li-ion battery electrodes.

中文翻译：

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富碳闪锌矿作为高效锂离子电池电极的自然资源

摘要 多种合成碳同素异形体在储能应用方面具有巨大潜力。已经有许多关于合成锂（Li）存储容量大于石墨理论极限（372 mAh/g，对应于 LiC6）的碳质负极材料的报道。然而，除了性能之外，可用资源和成本效率也是可能阻碍其开发的障碍。在这里，我们展示了富含碳的前寒武纪岩石“闪锌矿”作为锂离子电池阳极的自然资源。发现在结构改性后，完全锂化的“闪锌矿”的能量密度可以超过石墨的密度，变得与不可石墨化（“硬”）碳相当。对改性“闪锌矿”的高分辨率透射电子显微镜 (HRTEM) 研究表明，它由弯曲、弯曲、单层或堆叠石墨烯层的空间排列分形组成。通过分析完全锂化的“次闪石”的 7Li 核磁共振 (NMR) 谱的特征，我们得出结论，增强的存储容量主要是由于开放边缘的少量层状石墨烯薄片的存在。因此，我们建议将富含碳的“次石墨”作为锂离子电池电极的替代和有效自然资源。