rGO–Encapsulated Co/Ni dual–doped FeF3·0.33H2O nanoparticles enabling a high-rate and long-life iron (III) fluoride–lithium battery

•Sandwich architecture of rGO-encapsulated Ni/Co co-doped FeF3·0.33H2O was prepared.•Ni-doping facilitate mainly the capacity improvement by expanding the cell volume.•Co-doping enhance primarily the cycling stability by accelerating Li+ migration.•NC-FF are firmly encapsulated within rGO sheets by MOC bonding interaction.•NC-FF|Graphite full-cell shows a high reversible capacity and good cycle stability.