Shtepliuk Ivan, Vagin Mikhail, Khan Ziyauddin, Zakharov Alexei A, Iakimov Tihomir, Giannazzo Filippo, Ivanov Ivan G, Yakimova Rositsa
Department of Physics, Chemistry and Biology, Linköping University, SE-58183 Linköping, Sweden.
Laboratory of Organic Electronics, Department of Science and Technology, Linköping University, SE-60174 Norrköping, Sweden.
Nanomaterials (Basel). 2022 Jun 29;12(13):2229. doi: 10.3390/nano12132229.
Novel two-dimensional materials (2DMs) with balanced electrical conductivity and lithium (Li) storage capacity are desirable for next-generation rechargeable batteries as they may serve as high-performance anodes, improving output battery characteristics. Gaining an advanced understanding of the electrochemical behavior of lithium at the electrode surface and the changes in interior structure of 2DM-based electrodes caused by lithiation is a key component in the long-term process of the implementation of new electrodes into to a realistic device. Here, we showcase the advantages of bilayer-patched epitaxial graphene on 4H-SiC (0001) as a possible anode material in lithium-ion batteries. The presence of bilayer graphene patches is beneficial for the overall lithiation process because it results in enhanced quantum capacitance of the electrode and provides extra intercalation paths. By performing cyclic voltammetry and chronoamperometry measurements, we shed light on the redox behavior of lithium at the bilayer-patched epitaxial graphene electrode and find that the early-stage growth of lithium is governed by the instantaneous nucleation mechanism. The results also demonstrate the fast lithium-ion transport (~4.7-5.6 × 10 cm∙s) to the bilayer-patched epitaxial graphene electrode. Raman measurements complemented by in-depth statistical analysis and density functional theory calculations enable us to comprehend the lithiation effect on the properties of bilayer-patched epitaxial graphene and ascribe the lithium intercalation-induced Raman peak splitting to the disparity between graphene layers. The current results are helpful for further advancement of the design of graphene-based electrodes with targeted performance.
具有平衡电导率和锂存储容量的新型二维材料（2DMs）对于下一代可充电电池来说是理想之选，因为它们可作为高性能阳极，改善电池输出特性。深入了解锂在电极表面的电化学行为以及锂化作用导致的基于二维材料的电极内部结构变化，是将新型电极应用于实际设备的长期过程中的关键环节。在此，我们展示了4H-SiC（0001）上的双层补丁外延石墨烯作为锂离子电池中可能的阳极材料的优势。双层石墨烯补丁的存在有利于整个锂化过程，因为它会增强电极的量子电容并提供额外的嵌入路径。通过进行循环伏安法和计时电流法测量，我们揭示了锂在双层补丁外延石墨烯电极上的氧化还原行为，并发现锂的早期生长受瞬时成核机制控制。结果还表明锂离子向双层补丁外延石墨烯电极的快速传输（~4.7 - 5.6×10 cm∙s）。拉曼测量辅以深入的统计分析和密度泛函理论计算，使我们能够理解锂化对双层补丁外延石墨烯性质的影响，并将锂嵌入引起的拉曼峰分裂归因于石墨烯层之间的差异。目前的结果有助于进一步推进具有目标性能的基于石墨烯的电极设计。
