Sun Jinhua, Sadd Matthew, Edenborg Philip, Grönbeck Henrik, Thiesen Peter H, Xia Zhenyuan, Quintano Vanesa, Qiu Ren, Matic Aleksandar, Palermo Vincenzo
Materials and Manufacture, Department of Industrial and Materials Science, Chalmers University of Technology, Göteborg, Sweden.
Materials Physics, Department of Physics, Chalmers University of Technology, Göteborg, Sweden.
Sci Adv. 2021 May 28;7(22). doi: 10.1126/sciadv.abf0812. Print 2021 May.
Sodium, in contrast to other metals, cannot intercalate in graphite, hindering the use of this cheap, abundant element in rechargeable batteries. Here, we report a nanometric graphite-like anode for Na storage, formed by stacked graphene sheets functionalized only on one side, termed Janus graphene. The asymmetric functionalization allows reversible intercalation of Na, as monitored by operando Raman spectroelectrochemistry and visualized by imaging ellipsometry. Our Janus graphene has uniform pore size, controllable functionalization density, and few edges; it can store Na differently from graphite and stacked graphene. Density functional theory calculations demonstrate that Na preferably rests close to -NH group forming synergic ionic bonds to graphene, making the interaction process energetically favorable. The estimated sodium storage up to CNa is comparable to graphite for standard lithium ion batteries. Given such encouraging Na reversible intercalation behavior, our approach provides a way to design carbon-based materials for sodium ion batteries.
与其他金属不同，钠无法嵌入石墨中，这阻碍了这种廉价且储量丰富的元素在可充电电池中的应用。在此，我们报道了一种用于钠存储的纳米级类石墨阳极，它由仅一侧功能化的堆叠石墨烯片形成，称为Janus石墨烯。通过原位拉曼光谱电化学监测并通过成像椭偏法可视化，这种不对称功能化允许钠的可逆嵌入。我们的Janus石墨烯具有均匀的孔径、可控的功能化密度且边缘较少；它存储钠的方式与石墨和堆叠石墨烯不同。密度泛函理论计算表明，钠优选靠近 -NH基团，与石墨烯形成协同离子键，使相互作用过程在能量上有利。估计高达CNa的钠存储量与标准锂离子电池的石墨相当。鉴于这种令人鼓舞的钠可逆嵌入行为，我们的方法为设计用于钠离子电池的碳基材料提供了一条途径。
