An alumina-coated Fe₃O₄-reduced graphene oxide composite electrode as a stable anode for lithium-ion battery

Fe₃O₄-reduced graphene oxide (rGO) composites have been synthesized via an ethylene glycol-mediated solvothermal-polyol method. The electrochemical performances of the as-prepared Fe₃O₄-rGO electrode and alumina (Al₂O₃) film coated Fe₃O₄-rGO electrode using atomic layer deposition (ALD) were investigated. The results indicated that the ALD coating of Al₂O₃ greatly improved the electrochemical properties (especially cycling stability) of Fe₃O₄-rGO composite electrode as an anode for lithium-ion battery (LIB), resulting in the increase of reversible capacity from 94.1 mA h g^-1 to 717.4 mA h g^-1 after 200 cycles. The Al₂O₃ films retain sufficiently integral to limit the excessive growth of the interfacial layer between Fe₃O₄ and electrolyte, which in turn improves the electrochemical kinetics at the electrode/electrolyte interface and maintains a relatively stable interfacial resistance during whole discharge/charge cycles. The results presented in this study pave a new way to improve the stability of nanostructured anodes for LIBs.