Raccichini Rinaldo, Varzi Alberto, Chakravadhanula Venkata Sai Kiran, Kübel Christian, Passerini Stefano
Helmholtz Institute Ulm (HIU), Helmholtzstrasse 11, 89081 Ulm, Germany.
Karlsruhe Institute of Technology (KIT), P.O. Box 3640, 76021 Karlsruhe, Germany.
Sci Rep. 2016 Mar 30;6:23585. doi: 10.1038/srep23585.
Graphene is extensively investigated and promoted as a viable replacement for graphite, the state-of-the-art material for lithium-ion battery (LIB) anodes, although no clear evidence is available about improvements in terms of cycling stability, delithiation voltage and volumetric capacity. Here we report the microwave-assisted synthesis of a novel graphene-based material in ionic liquid (i.e., carved multilayer graphene with nested Fe3O4 nanoparticles), together with its extensive characterization via several physical and chemical techniques. When such a composite material is used as LIB anode, the carved paths traced by the Fe3O4 nanoparticles, and the unconverted metallic iron formed in-situ upon the 1(st) lithiation, result in enhanced rate capability and, especially at high specific currents (i.e., 5 A g(-1)), remarkable cycling stability (99% of specific capacity retention after 180 cycles), low average delithiation voltage (0.244 V) and a substantially increased volumetric capacity with respect to commercial graphite (58.8 Ah L(-1) vs. 9.6 Ah L(-1)).
石墨烯作为锂离子电池（LIB）阳极的最先进材料石墨的可行替代品，受到了广泛的研究和推广，尽管在循环稳定性、脱锂电压和体积容量方面的改进尚无明确证据。在此，我们报告了一种新型离子液体基石墨烯材料（即嵌套有Fe3O4纳米颗粒的刻蚀多层石墨烯）的微波辅助合成，以及通过多种物理和化学技术对其进行的广泛表征。当这种复合材料用作LIB阳极时，Fe3O4纳米颗粒所形成的刻蚀路径以及首次锂化时原位形成的未转化金属铁，可提高倍率性能，尤其是在高比电流（即5 A g(-1)）下，具有出色的循环稳定性（180次循环后比容量保持率为99%）、低平均脱锂电压（0.244 V），并且相对于商业石墨，体积容量大幅增加（58.8 Ah L(-1) 对比 9.6 Ah L(-1)）。
