A Surface Modification Strategy Towards Reversible Na-ion Intercalation on Graphitic Carbon Using Fluorinated Few-Layer Graphene
A Surface Modification Strategy Towards Reversible Na-ion Intercalation on Graphitic Carbon Using Fluorinated Few-Layer Graphene
复制标题
使用氟化少层石墨烯在石墨碳上实现可逆钠离子嵌入的表面改性策略
DOI：
10.1149/1945-7111/ac9c33
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发表时间：
2022
影响因子：
3.9
通讯作者：
van der Zande, Arend M.
中科院分区：
文献类型：
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作者：
Sarbapalli, Dipobrato;Lin, Yu-Hsiu;Stafford, Sean;Son, Jangyup;Mishra, Abhiroop;Hui, Jingshu;Nijamudheen, A;Romo, Adolfo I.;Gossage, Zachary T.;van der Zande, Arend M.
钠离子电池（nib）被认为是锂离子化学以外的一个有前途的候选者，然而，与nib相关的一个关键挑战是无法实现石墨阳极的嵌入。这种现象已经被研究过，并且被认为是由于钠嵌层石墨的热力学不稳定性引起的。我们最近的理论计算表明，使用氟表面改性剂可以实现热力学稳定的na插层石墨烯结构。在这里，我们提出的实验证据表明，使用循环伏安法（CV）、离子敏感扫描电化学显微镜（SECM）和原位拉曼光谱，在氟化少层石墨烯（F-FLG）结构中，Na+插入确实是可能的。SECM和拉曼光谱证实了Na+在F-FLG中的嵌入，而CV测量使我们能够量化Na插入F-FLG在NaC 14-18附近的化学计量。这些化学计量值高于先前报道的石墨中NaC 186的值。我们的实验表明，除了表面氟化外，可逆的Na+离子插入还需要预形成的li基SEI，从而突出了SEI在控制碱离子电池中离子转移动力学中的关键作用。总之，我们的研究结果强调了表面改性的使用以及对电极-电解质界面和界面相的仔细研究作为nib的使能策略。
Na-ion batteries (NIBs) are proposed as a promising candidate for beyond Li-ion chemistries, however, a key challenge associated with NIBs is the inability to achieve intercalation in graphite anodes. This phenomenon has been investigated and is believed to arise due to the thermodynamic instability of Na-intercalated graphite. We have recently demonstrated theoretical calculations showing it is possible to achieve thermodynamically stable Na-intercalated graphene structures with a fluorine surface modifier. Here, we present experimental evidence that Na+ intercalation is indeed possible in fluorinated few-layer graphene (F-FLG) structures using cyclic voltammetry (CV), ion-sensitive scanning electrochemical microscopy (SECM) and in situ Raman spectroscopy. SECM and Raman spectroscopy confirmed Na+ intercalation in F-FLG, while CV measurements allowed us to quantify Na-intercalated F-FLG stoichiometries around NaC 14–18. These stoichiometries are higher than the previously reported values of NaC 186 in graphite. Our experiments revealed that reversible Na+ ion intercalation also requires a pre-formed Li-based SEI in addition to the surface fluorination, thereby highlighting the critical role of SEI in controlling ion-transfer kinetics in alkali-ion batteries. In summary, our findings highlight the use of surface modification and careful study of electrode-electrolyte interfaces and interphases as an enabling strategy for NIBs.