Speed School of Engineering, University of Louisville, 2210 S. Brook st., Louisville, KY, 40208, USA.
Conn Center of Renewable Energy Research, University of Louisville, KY, USA.
Sci Rep. 2017 Jan 6;7:39944. doi: 10.1038/srep39944.
Graphite's capacity of intercalating lithium in rechargeable batteries is limited (theoretically, 372 mAh g) due to low diffusion within commensurately-stacked graphene layers. Graphene foam with highly enriched incommensurately-stacked layers was grown and applied as an active electrode in rechargeable batteries. A 93% incommensurate graphene foam demonstrated a reversible specific capacity of 1,540 mAh g with a 75% coulombic efficiency, and an 86% incommensurate sample achieves above 99% coulombic efficiency exhibiting 930 mAh g specific capacity. The structural and binding analysis of graphene show that lithium atoms highly intercalate within weakly interacting incommensurately-stacked graphene network, followed by a further flexible rearrangement of layers for a long-term stable cycling. We consider lithium intercalation model for multilayer graphene where capacity varies with N number of layers resulting LiC stoichiometry. The effective capacity of commonly used carbon-based rechargeable batteries can be significantly improved using incommensurate graphene as an anode material.
由于在共面堆叠的石墨烯层内扩散性差，石墨插层锂在可充电电池中的容量有限（理论上为 372 mAh g）。生长了高度富含非共面堆叠层的石墨烯泡沫，并将其用作可充电电池中的活性电极。具有 93%非共面的石墨烯泡沫表现出 1540 mAh g 的可逆比容量和 75%的库仑效率，而 86%非共面的样品的库仑效率超过 99%，具有 930 mAh g 的比容量。石墨烯的结构和结合分析表明，锂离子高度插层于弱相互作用的非共面堆叠石墨烯网络内，然后是层的进一步灵活重排，以实现长期稳定的循环。我们考虑了多层石墨烯的锂离子插层模型，其中容量随 N 个层数的变化而变化，导致 LiC 化学计量比发生变化。使用非共面石墨烯作为阳极材料，可以显著提高常用碳基可充电电池的有效容量。
