Surface-Dominated Sodium Storage Towards High Capacity and Ultrastable Anode Material for Sodium-Ion Batteries
Surface-Dominated Sodium Storage Towards High Capacity and Ultrastable Anode Material for Sodium-Ion Batteries
复制标题
面向钠离子电池的高容量和超稳定阳极材料的表面主导钠存储
DOI：
10.1002/adfm.201805371
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发表时间：
2018-11-21
影响因子：
19
通讯作者：
Xia, Hui
中科院分区：
文献类型：
--
作者：
Luo, Da;Xu, Jing;Xia, Hui
钠离子电池的发展受到钠离子输运动力学和电极材料在钠离子嵌入/脱嵌过程中结构不稳定的阻碍。在这项工作中，表面占主导地位的钠存储上的氧功能化的石墨烯纳米片（FGS）具有快速的表面氧化还原反应和强大的结构稳定性。通过两步热剥离法从氧化石墨中制备了氧含量和种类可调的FGS样品。表面引入的氧官能团可作为FGS电极的表面氧化还原位点，在0.05 A g（-1）的电流密度下，达到603 mAh g（-1）的高比容量，具有优异的倍率性能（在10 A g（-1）下为214 mAh g（-1））和超稳定的循环稳定性（在5 A g（-1）下10000次循环后容量保持率接近100%）。即使在循环伏安法的0.1 mV s（-1）的慢扫描速率下，约67.7%的容量来自表面吸附/脱附和表面氧化还原反应，表明FGS-700（在700 ℃下获得的FGS样品）电极的表面主导的Na存储。目前的工作表明，表面氧功能化是一种有效的策略，以开发高性能的石墨烯基阳极，由于表面占主导地位的钠存储与改善的反应动力学和抑制结构变化。
The development of sodium-ion batteries is hindered by the poor Na+ transport kinetics and structural instability of electrode materials during Na+ intercalation/deintercalation. In this work, surface-dominated Na storage is demonstrated on the oxygen-functionalized graphene nanosheets (FGS) with fast surface redox reaction and robust structural stability. The FGS samples with tunable oxygen contents and species are fabricated via a two-step thermal exfoliation method from graphite oxides. The surface-induced oxygen functional groups can serve as the surface-redox sites for the FGS electrode, attaining a high specific capacity of 603 mAh g(-1) at a current density of 0.05 A g(-1), excellent rate capability (214 mAh g(-1) at 10 A g(-1)), and ultrastable cycling stability (capacity retention close to 100% after 10 000 cycles at 5 A g(-1)). Even at a slow scan rate of 0.1 mV s(-1) for cyclic voltammetry, about 67.7% capacity is contributed from the surface adsorption/desorption and surface-redox reaction, suggesting surface-dominated Na storage for the FGS-700 (FGS sample obtained at 700 degrees C) electrode. The present work demonstrates that the surface oxygen functionalization is an effective strategy to develop high-performance graphene-based anodes due to the surface-dominated Na storage with improved reaction kinetics and suppressed structural variation.