“…Due to the low melting point of metallic Li (about 180 C) the local overheat can trigger a disastrous thermal runaway. [216,219±221] Several approaches have been pursued to improve the rechargeability and reliability of the metallic lithium electrode: i) by using liquid electrolytes that are less reactive toward lithium (e.g., highly purified or ªadditive-stabilizedº electrolytes); [96,153,157,158,164,222±234] ii) by using polymer electrolytes; [49,50,114±118,163,217,235] iii) by adding surface active agents such as hydrocarbons, quarternary ammonium salts, and others that level the regrowth of metallic lithium; [208,209,215,227,228,236±239] iv) by controlling the properties of the metal surface and of the SEI using additives such as CO 2 , [151,164,240±249] N 2 O, [240] S x 2± , [240,250] HF, [162,251±255] and H 2 O [164,243,256] (the additives may influence both the film formation and lithium plating process); v) by coating the lithium with a lithium-ion conducting membrane; [257±260] vi) by adding scavengers to the electrolyte that dissolve the dendritic lithium filaments; [148,180] vii) by using mechanical pressure to suppress dendritic lithium growth; [46,261,262] and viii) by ªlow-temperature pre-cyclingº. [263,264] However, all of the above attempts brought only partial improvements to the cycle life of the lithium electrode.…”