Strongly anchored MnO nanoparticles on graphene as high-performance anode materials for lithium-ion batteries

Abstract

Manganous oxide (MnO) nanoparticles strongly anchored on reduced graphene oxide (RGO) have been synthesized by precipitating MnO precursor on RGO surface followed by an annealing process. The MnO/RGO composite has a homogeneous distribution of MnO nanoparticles on electrically conductive RGO, showing more uniform and reduced nanoparticle sizes of MnO than bare MnO owing to the dispersion effect of RGO. The RGO prevents the aggregation and thus increases the contact area of MnO with the electrolyte; The RGO also provides electrically conductive networks for fast charge transfer and buffers the volume change of MnO during lithium intercalation; as a result, the MnO/RGO electrode shows improved performances than the bare MnO electrode in terms of higher specific capacity, superior cycling stability, and enhanced rate capability. The MnO/RGO electrode exhibits an initial discharge/charge capacity of 919/552 mA h g−1 at 0.3 A g−1 and retains a discharge capacity of 544 mA h g−1 after 60 cycles as compared to the bare MnO electrode which shows a rapidly declined specific capacity and only retains 249 mA h g−1 after 60 cycles. The MnO/RGO electrode also displays enhanced specific capacity after testing at different rates. The improved performance of MnO/RGO can be attributed to the strong interphase interaction between MnO and RGO flakes.