Department of Materials Science , Fudan University , Shanghai 200433 , China.
Institute for Superconducting and Electronic Materials , University of Wollongong , North Wollongong , New South Wales 2522 , Australia.
ACS Nano. 2018 Apr 24;12(4):3816-3824. doi: 10.1021/acsnano.8b01033. Epub 2018 Apr 6.
MgH nanoparticles (NPs) uniformly anchored on graphene (GR) are fabricated based on a bottom-up self-assembly strategy as anode materials for lithium-ion batteries (LIBs). Monodisperse MgH NPs with an average particle size of ∼13.8 nm are self-assembled on the flexible GR, forming interleaved MgH/GR (GMH) composite architectures. Such nanoarchitecture could effectively constrain the aggregation of active materials, buffer the strain of volume changes, and facilitate the electron/lithium ion transfer of the whole electrode, leading to a significant enhancement of the lithium storage capacity of the GMH composite. Furthermore, the performances of GMH composite as anode materials for LIBs are enabled largely through robust interfacial interactions with poly(methyl methacrylate) (PMMA) binder, which plays multifunctional roles in forming a favorable solid-electrolyte interphase (SEI) film, alleviating the volume expansion and detachment of active materials, and maintaining the structural integrity of the whole electrode. As a result, these synergistic effects endow the obtained GMH composite with a significantly enhanced reversible capacity and cyclability as well as a good rate capability. The GMH composite with 50 wt % MgH delivers a high reversible capacity of 946 mA h g at 100 mA g after 100 cycles and a capacity of 395 mAh g at a high current density of 2000 mA g after 1000 cycles.
基于自下而上的自组装策略，制备了均匀锚定在石墨烯（GR）上的 MgH 纳米颗粒（NPs）作为锂离子电池（LIBs）的阳极材料。具有平均粒径约为 13.8nm 的单分散 MgH NPs 自组装在柔性 GR 上，形成交错的 MgH/GR（GMH）复合结构。这种纳米结构可以有效地抑制活性材料的聚集，缓冲体积变化的应变，并促进整个电极的电子/锂离子转移，从而显著提高 GMH 复合材料的储锂能力。此外，GMH 复合材料作为 LIBs 的阳极材料的性能在很大程度上得益于与聚甲基丙烯酸甲酯（PMMA）粘合剂之间的强界面相互作用，这种相互作用在形成有利的固体电解质界面（SEI）膜、缓解活性材料的体积膨胀和脱落以及保持整个电极的结构完整性方面发挥了多种功能。因此，这些协同效应赋予了所获得的 GMH 复合材料显著增强的可逆容量和循环稳定性以及良好的倍率性能。在 100mA/g 下循环 100 次后，具有 50wt%MgH 的 GMH 复合材料具有 946mAh/g 的高可逆容量，在 1000 次循环后在 2000mA/g 的高电流密度下具有 395mAh/g 的容量。
