Practical　applications　of　lithium　metal　anodes　are　gravely　impeded　by　inhomogeneous　lithium　deposition,　which　results　in　dendrite　growth.　Electrolyte　additives　are　proven　to　be　effective　in　improving　performance　but　usually　serve　only　a　single　function.　Herein,　nitrofullerene　is　introduced　as　a　bifunctional　additive　with　a　smoothing　effect　and　forms　a　protective　solid　electrolyte　interphase　(SEI)　layer　on　stable　lithium　metal　anodes.　By　design,　nitro-C-60　can　gather　on　electrode　protuberances　via　electrostatic　interactions　and　then　be　reduced　to　NO2-　and　insoluble　Co-60.　Next,　the　C-60　anchors　on　the　uneven　groove　of　the　lithium　surface,　resulting　in　a　homogeneous　distribution　of　Li　ions.　Finally,　NO2-　anions　can　react　with　metallic　Li　to　build　a　compact　and　stable　SEI　with　high　ion　transport.　With　a　5　mM　nitro-C-60　additive,　Li-Li　symmetric　cells　show　superior　cycle　stability　in　both　carbonate　and　ether　electrolytes,　Li-sulfur　batteries　with　a　high　cathode　loading　(10.6　mg　cm(-2),　6　mAh　cm(-2))　can　achieve　improved　cycle　retention　of　63.2%　over　100　cycles　in　a　carbonate　electrolyte,　and　full　cells　paired　with　a　high-areal-capacity　LiNi0.6Co0.2Mn0.2O2　cathode　(3.5　mAh　cm(-2))　exhibit　a　significantly　enhanced　cycle　lifespan　even　under　lean　electrolyte