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Neat Design for the Structure of Electrode To Optimize the Lithium-Ion Battery Performance
- Zhao, Yongjie, Ding, Caihua, Hao, Yanan, Zhai, Ximei, Wang, Chengzhi, Li, Yutao, Li, Jingbo, Jin, Haibo
- ACS applied materials & interfaces 2018 v.10 no.32 pp. 27106-27115
- X-ray diffraction, anisotropy, electrodes, energy, freeze drying, graphene, lithium, lithium batteries, milling, nanoparticles, scanning electron microscopy, shrinkage, synergism, transmission electron microscopy
- The appearance of mechanical cracks originated from anisotropic expansion and shrinkage of electrode particles during Li⁺ de/intercalation is a major cause of the capacity fading in Li-ion batteries. Well-designed and controlled nanostructures of electrodes have shown a prominent prospect for solving this obstacle. Here, we report a novel and convenient strategy for the preparation of graphene nanoscroll wrapping Nb₂O₅ nanoparticles (denoted as T-Nb₂O₅/G). First, high energy ball milling is conducted to acquire softly agglomerated T-Nb₂O₅ nanoparticles owing to its spontaneous reduction of surface energy among these single particles. Then freeze-drying leads to the formation of graphene nanoscroll, which easily realizes the in situ wrapping over softly agglomerated T-Nb₂O₅ nanoparticles. Extended cycling tests demonstrate that such T-Nb₂O₅/G yields a high reversible specific capacity of 222 mA h g–¹ over 700 cycles at 1C. The dominated surface capacitive insertion processes possessing favorable kinetics enable T-Nb₂O₅/G to exhibit excellent rate performance, which achieve a capacity of 110 mA h g–¹ at 10C. A combined ex situ X-ray diffraction, scanning electron microscopy, and transmission electron microscopy investigation reveal that the long-term cycling stability of T-Nb₂O₅/G is attributed to the excellent structural stability of the electrode, in which the synergistic effect between the softly agglomerated T-Nb₂O₅ nanoparticles and graphene nanoscroll prevents the formation of mechanical cracks.