Magnesium\nHydride Nanoparticles Self-Assembled on\nGraphene as Anode Material for High-Performance Lithium-Ion Batteries

Abstract

MgH₂ nanoparticles (NPs) uniformly anchored on graphene\n(GR) are fabricated based on a bottom-up self-assembly strategy as\nanode materials for lithium-ion batteries (LIBs). Monodisperse MgH₂ NPs with an average particle size of ∼13.8 nm are\nself-assembled on the flexible GR, forming interleaved MgH₂/GR (GMH) composite architectures. Such nanoarchitecture could effectively\nconstrain the aggregation of active materials, buffer the strain of\nvolume changes, and facilitate the electron/lithium ion transfer of\nthe whole electrode, leading to a significant enhancement of the lithium\nstorage capacity of the GMH composite. Furthermore, the performances\nof GMH composite as anode materials for LIBs are enabled largely through\nrobust interfacial interactions with poly­(methyl methacrylate) (PMMA)\nbinder, which plays multifunctional roles in forming a favorable solid-electrolyte\ninterphase (SEI) film, alleviating the volume expansion and detachment\nof active materials, and maintaining the structural integrity of the\nwhole electrode. As a result, these synergistic effects endow the\nobtained GMH composite with a significantly enhanced reversible capacity\nand cyclability as well as a good rate capability. The GMH composite\nwith 50 wt % MgH₂ delivers a high reversible capacity of\n946 mA h g^–1 at 100 mA g ^–1 after\n100 cycles and a capacity of 395 mAh g^–1 at a high\ncurrent density of 2000 mA g^–1 after 1000 cycles.